1No person may be deprived of their liberty other than in the circumstances and in the manner provided for by the law.
2Any person deprived of their liberty has the right to be notified without delay and in a language they can understand of the reasons for their detention and of their rights. They must be given the opportunity to exercise their rights, in particular, the right to have their next-of-kin informed.
3Any person in pre-trial detention has the right to be brought before a court without delay. The court decides whether the person must remain in detention or be released. Any person in pre-trial detention has the right to have their case decided within a reasonable time.
4Any person who has been deprived of their liberty by a body other than a court has the right to have recourse to a court at any time. The court shall decide as quickly as possible on the legality of their detention.
Overview
Article 31 of the Federal Constitution protects personal liberty from arbitrary state interference. It regulates when and how the state may deprive a person of liberty.
What does the provision regulate?
The provision establishes four central rules: First, only a law itself may determine when deprivation of liberty is permitted (statutory reservation). Second, every detained person must be informed immediately of the reasons. Third, persons in pre-trial detention have the right to be brought before a judge. Fourth, any person who has not been detained by a court may call upon a court at any time.
Who is affected?
Every person in Switzerland may invoke this fundamental right. This applies to both Swiss citizens and foreigners. Typical cases are pre-trial detention for criminal offences, detention pending deportation for foreigners without residence rights, or involuntary commitment to psychiatric clinics.
Concrete examples
If the police arrest someone on suspicion of theft, they must immediately inform the person of the reason and bring them before a judge within 24 hours. The judge then examines whether the detention is justified. For foreigners without valid papers, the authorities may order detention pending deportation, but only if a law expressly permits this.
Legal consequences
Violations of these rules make the deprivation of liberty unlawful. The affected person may demand immediate release and is entitled to damages. Authorities must observe strict deadlines and may only deprive liberty for legally defined reasons.
Art. 31 BV — Deprivation of Liberty
#Doctrine
#1. Legislative History
N. 1 The current Federal Constitution codifies, in Art. 31, explicit and four-part guarantees in cases of deprivation of liberty. The former Federal Constitution of 1874 contained no corresponding provision. Under the old Constitution, however, the Federal Supreme Court had already developed minimum guarantees on the basis of the unwritten habeas corpus fundamental right and the general right to liberty (cf. Häfelin/Haller/Keller/Thurnherr, Schweizerisches Bundesstaatsrecht, 10th ed. 2020, N 404 ff.).
N. 2 In the preliminary draft of 1995, the later provision was not yet in its final form; the explanatory report on the 1995 preliminary draft (VE 1995) dealt on pp. 66 f. with the systematic demarcation between classical fundamental rights and newly introduced social objectives. Art. 31 BV in its current form corresponds in substance to Art. 27 of the Federal Council's draft of 1996 (VE 96). In its message of 20 November 1996, the Federal Council noted that Art. 27 VE 96 had no corresponding provision in the previous Constitution, but that the guarantees had already been secured by unwritten constitutional law and the ECHR (BBl 1997 I 185 f.; BBl 1997 I 563, 594). The objective of the total revision was therefore the updating of existing constitutional law and a clearer, more transparent codification of procedural guarantees.
N. 3 During the parliamentary deliberations, a divergence arose between the National Council and the Council of States regarding paragraph 2. The National Council added, as a new sentence, the explicit right to have one's next of kin notified. Rapporteur Marty Dick (R, TI) explained the committee's position to the Council of States, recommending agreement with the National Council: «Nous estimons que la différence n'est pas importante et surtout qu'elle ne mérite pas une divergence. Néanmoins, nous pensons que la version du Conseil national n'est pas très heureuse parce qu'on peut peut-être imaginer que le fait de faire avertir …» (AB 1998 SR). The Council of States ultimately concurred with the National Council. The conciliation conference resolved the remaining divergences on 14/15 December 1998; both chambers adopted the text in the final vote on 18 December 1998.
N. 4 The four-part structure of the provision — lawfulness (para. 1), rights to information (para. 2), appearance before a judge in pre-trial detention (para. 3), general judicial review of detention (para. 4) — deliberately corresponds to the various partial guarantees enshrined in Art. 5 ECHR. With the entry into force of the Code of Criminal Procedure (CrimPC) on 1 January 2011, the procedural guarantees set out in Art. 31 BV were comprehensively concretised at the statutory level (Art. 197 ff. CrimPC).
#2. Systematic Classification
N. 5 Art. 31 BV belongs to the second chapter of the Federal Constitution (Fundamental Rights, Art. 7–36 BV). The provision stands in a close systematic relationship to Art. 10 para. 2 BV (personal liberty, in particular freedom of movement), which protects the substantive right, whereas Art. 31 BV consolidates the procedural guarantees applicable when personal liberty is infringed through deprivation of liberty. ↔ Art. 10 para. 2 BV.
N. 6 In relation to the general procedural guarantees of Art. 29–30 BV, Art. 31 BV constitutes a lex specialis: to the extent that deprivation of liberty is at issue, the specific guarantees of Art. 31 BV take precedence. In addition, the supplementary procedural guarantees (in particular the right to be heard under Art. 29 para. 2 BV) apply subsidiarily in detention review proceedings (BGE 133 I 270 E. 3.1). → Art. 29 BV; → Art. 30 BV.
N. 7 Art. 31 BV corresponds in its essential substantive content to Art. 5 ECHR (right to liberty and security) and Art. 9 ICCPR. Both instruments are legally binding on Switzerland (ECHR since 1974, ICCPR since 1992). The Federal Supreme Court interprets Art. 31 BV in conformity with the conventions to the extent possible, but goes beyond the protective scope of Art. 5 para. 4 ECHR with regard to Art. 31 para. 4 BV (→ N. 23 ff.). → Art. 190 BV.
N. 8 For restrictions on fundamental rights, the general limitation regime of Art. 36 BV applies: a legal basis, a public interest and proportionality. Art. 36 para. 1 sentence 2 BV requires, for serious restrictions — of which deprivation of liberty is one — a basis in statute itself. This corresponds to the wording of Art. 31 para. 1 BV. → Art. 36 BV.
#3. Elements of the Provision / Normative Content
3.1 Concept of Deprivation of Liberty (para. 1)
N. 9 The central definitional element of all four paragraphs is the concept of deprivation of liberty (privation de liberté / privazione della libertà). According to consistent case law, this is understood as the confinement of a person to a specific, limited place for a certain duration, carried out by a public authority against or without the will of the person concerned. The decisive factors are the type, duration, extent and intensity of the measure in its overall effect (BGE 134 I 140 E. 3.2). Typical examples are pre-trial detention and detention on remand, involuntary placement for care purposes, and administrative detention under immigration law. Mere restrictions on liberty — such as a ban on entering a specified area — do not fall under Art. 31 BV but under Art. 10 para. 2 BV (BGE 134 I 140 E. 3.3).
N. 10 The deprivation of liberty must be ordered by a public authority. Acts by private individuals (e.g. citizen's arrest) are covered insofar as public authorities authorise or tolerate them. The designation of the measure under domestic law is irrelevant; what is decisive is its actual effect (Müller/Schefer, Grundrechte in der Schweiz, 4th ed. 2008, pp. 95 f.).
3.2 Lawfulness (para. 1)
N. 11 Paragraph 1 contains a dual requirement of legality: the deprivation of liberty must occur in the cases provided for by statute itself (substantive conditions) and in the manner prescribed by statute (procedure). The statute must define the interferences with sufficient precision to enable the persons concerned to regulate their conduct accordingly. In the context of administrative detention, the Federal Supreme Court has confirmed that the requirement of a statutory basis — i.e. in a formal act of parliament, not merely in an ordinance — is mandatory (BGE 142 I 135 E. 4.1; BGE 140 II 1 E. 2.1). In the case of anticipatory execution of a sentence, the legal basis remains the detention warrant issued in criminal proceedings; the anticipated custodial sentence alone does not justify the deprivation of liberty (BGE 143 IV 160 E. 2.2).
N. 12 The numerus clausus of grounds for detention (risk of flight, risk of collusion, risk of reoffending, risk of completion of the offence; Art. 221 CrimPC) is the statutory expression of the requirement of substantive legality under para. 1. A strong suspicion of the commission of an offence must always be additionally present. The Federal Supreme Court reviews the proportionality of detention independently and comprehensively, i.e. without deference to the assessment of the lower instance (BGE 132 I 21 E. 2.1; BGE 133 I 270 E. 2.2).
3.3 Rights to Information (para. 2)
N. 13 Paragraph 2 contains three separate entitlements that arise immediately upon detention: (1) the right to be informed of the grounds for the deprivation of liberty in a language the person understands; (2) the right to assert one's rights; (3) the right to have one's next of kin notified. The right to notification of next of kin was inserted by the National Council during the parliamentary proceedings (→ N. 3).
N. 14 The criterion of a «language the person understands» is not limited to official languages; it also covers the case where the detained person does not understand any official language. If necessary, interpreters must be provided. This guarantee is a precondition for the effective exercise of the remaining rights. The right to free legal assistance in detention review proceedings (Art. 29 para. 3 BV) flows from the right to information and the right to assert one's rights under para. 2 and constitutes the procedural extension thereof (BGE 134 I 92 E. 1 ff.).
3.4 Appearance before a Judge in Pre-Trial Detention (para. 3)
N. 15 Paragraph 3 applies specifically to pre-trial detention (detention in criminal proceedings within the meaning of Art. 221 f. CrimPC). It contains two entitlements: (1) prompt appearance before a judge; (2) judgment within a reasonable time. The first entitlement corresponds to Art. 5 para. 3 ECHR, according to which every person arrested must be «brought promptly before a judge or other officer authorised by law to exercise judicial power».
N. 16 The requirement of expedition is the guiding principle in criminal pre-trial detention. The Federal Supreme Court has derived from this that the statutory suspension of time limits for appeals to the Federal Supreme Court (Art. 46 para. 1 BGG) does not apply in detention cases (BGE 133 I 270 E. 1.2.2). Appeals against detention must always be treated as urgent.
N. 17 The requirement of judgment within a reasonable time (para. 3 sentence 2) prohibits excessive duration of detention. Such excess occurs when the length of detention approaches the anticipated liberty-restricting sanction. In assessing this, the gravity of the charges, the complexity of the proceedings and the conduct of the parties must be taken into account (BGE 133 I 168 E. 4.1; BGE 128 I 149 E. 2.2.1). Extradition detention that is creditable against the sentence must in principle be included in the proportionality assessment (BGE 133 I 168 E. 4.1).
3.5 General Right to Judicial Review of Detention (para. 4)
N. 18 Paragraph 4 applies to all cases of deprivation of liberty that have not been ordered by a court. The provision establishes an at any time right to apply to a court. This goes further than Art. 5 para. 4 ECHR, which merely guarantees the right to make an application. Art. 31 para. 4 BV grants the detained person the right to determine the timing of the judicial application; the court must accept the application and decide on it as quickly as possible (BGE 137 I 23 E. 2.4.2 f.).
N. 19 Paragraph 4 constitutes an independent guarantee in relation to the mandatory detention review rules of ordinary law (e.g. Art. 80 para. 2 AuG: 96-hour time limit). Art. 80 para. 2 AuG is directed at the enforcement authority; Art. 31 para. 4 BV confers on the detained person itself the right to apply to a court. Both provisions may be applied in parallel (BGE 137 I 23 E. 2.4.4 f.). The initial detention review must take place «as quickly as possible» — in Dublin detention, the 96-hour time limit under Art. 80 para. 2 AuG serves as the benchmark (BGE 142 I 135 E. 3.3).
#4. Legal Consequences
N. 20 A deprivation of liberty effected without a legal basis or in a manner contrary to statute is unlawful. The immediate legal consequence is the release of the detained person. The detention judge must terminate an unconstitutional deprivation of liberty ex officio; no application or objection is required.
N. 21 Violations of the guarantees in paragraph 2 (rights to information) do not automatically lead to release from detention, but may result in exclusion of evidence in criminal proceedings or affect the admissibility of statements. In detention review proceedings they constitute independent grounds of complaint.
N. 22 The right to judicial review of detention under paragraph 4 does not require a current interest, once ECHR guarantees are invoked in a plausible manner or fundamental questions arise that are capable of recurring at any time (BGE 142 I 135 E. 1.3; BGE 136 I 274 E. 1.3). A violation of Art. 5 para. 4 ECHR or Art. 31 para. 4 BV may be sanctioned by a declaratory judgment after release from detention (BGE 142 I 135 E. 3.4 and 6.1).
#5. Contested Issues
N. 23 Relationship between Art. 31 para. 4 BV and Art. 5 para. 4 ECHR: Academic doctrine is divided on how far the protective scope of Art. 31 para. 4 BV extends beyond Art. 5 para. 4 ECHR. Müller/Schefer (Grundrechte in der Schweiz, 4th ed. 2008, p. 109) emphasise that the «at any time» right to apply under Art. 31 para. 4 BV confers a more active standing on the detained person than Art. 5 para. 4 ECHR, which merely provides for the right «to take proceedings». The Federal Supreme Court confirmed this interpretation in BGE 137 I 23 E. 2.4.2 and qualified Art. 31 para. 4 BV as a specific manifestation of the prohibition of denial of justice. Kiener/Kälin (Grundrechte, 2nd ed. 2013, p. 66) share this view but urge caution regarding the question of how quickly the court must decide.
N. 24 Applicability of detention guarantees in anticipatory execution of sentence: It was disputed whether a detained person who has consented to anticipatory execution of sentence may apply for release at any time. The Federal Supreme Court answered in the affirmative in BGE 143 IV 160 E. 2.3, clarifying earlier case law (BGE 104 Ib 24; BGE 117 Ia 72): consent is revocable; upon the filing of an application for release, the statutory conditions for detention under Art. 221 CrimPC must be examined. Rhinow/Schefer/Uebersax (Schweizerisches Verfassungsrecht, 3rd ed. 2016, N 1553) had already previously taken the view that the procedural guarantees of Art. 31 BV must in principle be indefeasible.
N. 25 Demarcation between deprivation of liberty and restriction of liberty: Academic doctrine discusses the criteria for this demarcation. The Federal Supreme Court's formula (type, duration, extent, intensity: BGE 134 I 140 E. 3.2) corresponds to the case law of the ECtHR (Guzzardi v. Italy, 6 November 1980, § 92). Häfelin/Haller/Keller/Thurnherr (Bundesstaatsrecht, 10th ed. 2020, N 409) note that brief police checks do not, under certain conditions, yet constitute a deprivation of liberty, whereas detention lasting several hours in principle falls within that concept.
N. 26 Declaratory interest after release from detention: In both case law and academic doctrine it is recognised that a current legal interest in a detention complaint may exceptionally persist after release where ECHR claims are at issue (BGE 136 I 274 E. 1.3; BGE 142 I 135 E. 1.3.2). Rhinow/Schefer/Uebersax (Verfassungsrecht, 3rd ed. 2016, N 1557) welcome this case law as a necessary consequence of the interest in rehabilitation flowing from the ECHR.
#6. Practical Notes
N. 27 Direct recourse to the courts: Art. 31 para. 4 BV allows a person to apply to a court immediately upon deprivation of liberty and independently of any official detention review proceedings. The enforcement authority may not defer the application until the expiry of a statutory time limit (e.g. 96 hours under Art. 80 para. 2 AuG) or treat it as moot (BGE 137 I 23 E. 2.5). This also applies to Dublin detention under Art. 76a AuG (BGE 142 I 135 E. 3.2 f.).
N. 28 Requirement of expedition in detention appeals: Appeals against pre-trial detention must be treated as urgent; the suspension of time limits during court recesses under Art. 46 para. 1 BGG does not apply (BGE 133 I 270 E. 1.2.2). The same applies, according to the case law of the Second Public Law Division, to immigration detention in certain constellations (BGE 142 I 135 E. 1.2.3).
N. 29 Proportionality of duration of detention: The detention judge must actively obtain the case files necessary to assess proportionality; blanket assessments made without knowledge of the file violate Art. 29 para. 2 BV (BGE 133 I 270 E. 3.4.3). Where the duration of detention approaches the anticipated sentence, particular care is required, since the sentencing court tends to credit pre-trial detention against the sentence (BGE 133 I 168 E. 4.1).
N. 30 Alternative measures: Detention is a measure of last resort; the detention judge must always examine whether alternative measures (bail, surrender of passport and identity documents, electronic monitoring; Art. 237 CrimPC) would equally fulfil the purpose of detention. Failure to carry out this examination violates Art. 29 para. 2 BV and Art. 31 para. 3 BV (BGE 133 I 270 E. 3.3).
N. 31 Duty of the detention judge to give reasons: Detention decisions are subject to enhanced reasoning requirements because they constitute a serious interference with personal liberty. This applies in particular where only a single judicial instance has jurisdiction (BGE 133 I 270 E. 3.5.1). With the entry into force of the CrimPC (Art. 224 ff.), the procedural guarantees for the ordering of detention are today comprehensively regulated.
N. 32 Parallel ECHR guarantees: Art. 31 BV must always be interpreted in the light of Art. 5 ECHR and the case law of the ECtHR. Where Art. 31 BV has the same protective scope (paras. 1–3), Strasbourg practice serves as the authoritative interpretive aid; where Art. 31 para. 4 BV goes beyond Art. 5 para. 4 ECHR (→ N. 23), the constitutional minimum standard forms the lower threshold.
#Case Law
The case law on Art. 31 BV is structured according to the various forms of deprivation of liberty and the procedural guarantees. The Federal Supreme Court has developed comprehensive jurisprudence that specifies both the material requirements and the procedural demands.
#Lawfulness of Deprivation of Liberty (Para. 1)
BGE 140 II 1 (9.12.2013) Principle of lawfulness of administrative deprivation of liberty in immigration law. The decision specifies that a second administrative detention in the same removal procedure is only permissible when the circumstances have changed in a decisive way.
«The ordering of detention pending deportation after a release from custody in the same removal procedure requires that new circumstances of decisive importance exist.»
BGE 134 I 140 (31.1.2008) Distinction between restriction of liberty and deprivation of liberty in protective measures against violence. This landmark decision defines the threshold for constitutionally relevant deprivation of liberty.
«The concept of ‹deprivation of liberty› within the meaning of Art. 5 ECHR and Art. 31 BV is not to be understood merely as detention in the narrow sense. Conversely, not every type of restriction of liberty falls under this guarantee, but only restrictions of liberty of a certain extent and certain intensity.»
#Information and Notification Rights (Para. 2)
BGE 134 I 92 (1.1.2008) Right to free legal representation in immigration detention review proceedings. The decision specifies the rights of detained persons in enforcement detention.
«Enforcement detention requires a ‹pending expulsion procedure› and is therefore based on Art. 5 no. 1 lit. f ECHR under convention law.»
#Pre-trial Detention and Judicial Appearance (Para. 3)
BGE 133 I 270 (14.9.2007) Suspension of time limits in criminal procedural detention and acceleration requirement. This leading decision emphasizes the particular urgency of detention appeals.
«The statutory suspension of time limits for appeals to the Federal Supreme Court does not apply in cases concerning criminal procedural detention.»
BGE 133 I 168 (11.5.2007) Principle of proportionality regarding the duration of pre-trial detention. The decision develops criteria for the maximum duration of detention in relation to the expected sentence.
«It violates the principle of proportionality when the duration of pre-trial detention approaches the actual expected prison sentence in terms of time.»
BGE 132 I 21 (23.3.2006) Risk of collusion as grounds for custody detention after indictment. The decision specifies the particular grounds for detention in serious offenses.
«Collusion means in particular that the accused reaches an understanding with witnesses, informants, experts or co-accused or induces them to make false statements.»
BGE 128 I 149 (2.5.2002) Particular risk of collusion in sexual offenses and acceleration requirement. The decision shows the limits of detention duration in difficult expert assessments.
«The complaint that the acceleration requirement has been violated is subsidiary in detention review proceedings. It can only be heard if it was not already the subject of ordinary procedural complaints.»
BGE 139 IV 270 (16.10.2013) Custody detention during appeal proceedings. The decision addresses the distribution of jurisdiction between different procedural stages.
«Despite the wording of Art. 233 StPO, it does not contradict the sense and purpose of this provision if the procedural management of the appellate court orders or extends custody detention.»
BGE 143 IV 160 (16.2.2017) Early execution of sentence and measures in applications for release from custody. The decision clarifies the legal nature of pre-trial detention in case of expected conviction.
«Early execution of sentence refers solely to the execution of pre-trial and custody detention. The legal basis for the associated deprivation of liberty is not the expected sentence, but the applicable detention order.»
BGE 143 IV 316 (16.8.2017) Urgent suspicion of crime in crimes against humanity. This decision shows the special requirements for international crimes.
«Urgent suspicion of crime in detention review proceedings, particularly at the beginning of criminal investigation; evidentiary requirements for torture allegations.»
BGE 135 I 71 (20.1.2009) Prior offense requirement for the detention ground of risk of repetition. The decision specifies the consideration of previous convictions in detention review.
«Art. 369 StGB must also be observed by the detention judge with the effect that previous convictions removed from the criminal record may not be considered when examining the criminal procedural detention ground of risk of repetition.»
#Right to Judicial Review of Detention (Para. 4)
BGE 142 I 135 (2.5.2016) Right to rapid judicial review in administrative detention in Dublin procedures. This important decision strengthens the rights of asylum seekers in detention review.
«If the person concerned requests judicial review of the detention order for the first time, this must take place as quickly as possible. The 8-day period according to Art. 80a para. 4 AuG does not concern the initial judicial review of detention.»
BGE 137 I 23 (1.1.2010) Relationship of Art. 31 para. 4 BV to immigration law. The groundbreaking decision clarifies the right to invoke a court at any time.
«Art. 31 para. 4 BV guarantees the right to invoke a court at any time. This court decides as quickly as possible on the lawfulness of the deprivation of liberty.»
BGE 139 I 206 (1.1.2013) Challenge of detention decisions in case of extensions. The decision addresses the standing to appeal in subsequent detention decisions.
«The challenge of an immigration detention decision remains admissible even if it has been replaced by an extension decision, provided there is a current interest in legal protection.»
BGE 136 I 274 (11.5.2010) Current interest in detention appeals after interim release. The decision addresses the requirements for continued treatment of detention appeals.
«Under special circumstances, the Federal Supreme Court still handles a detention appeal even when the appellant has been released in the interim.»
#Immigration Administrative Detention
BGE 139 I 206 (1.1.2013) Maximum duration and proportionality of detention pending deportation. This landmark decision specifies the limits of administrative detention.
«The maximum duration of immigration detention is generally six months, but may be extended to a maximum of eighteen months under special circumstances.»
BGE 137 I 296 (1.1.2010) Release during appeal proceedings. The decision addresses the interest in legal protection in case of interim release.
«The current interest in legal protection for the handling of a detention appeal can persist even after interim release if special circumstances exist.»