Detaining a foreign national for 24 hours after a decision to release her/him violates the French Constitution.
In a decision dated September 12, 20251, the French Constitutional Court (Conseil Constitutionnel) has vetoed one of the provisions of the recent immigration law of January 26, 20242, extending from 10 to 24 hours the period during which a foreign national may be held in custody despite a decision by a judge ordering her/his release, awaiting a possible appeal by the public prosecutor.
When a foreign national is placed in administrative detention, i.e., deprived of freedom awaiting possible deportation to their country of origin, the conditions of her/his detention must be regularly reviewed by a judge who may release them in the event of any irregularities.
In the latter case, the appeal lodged by the procureur de la République is not suspensive (i.e. it does not prevent release), unless the latter obtains from the first president of the court of appeal (Cour d’appel) that the appeal be declared suspensive.
In order to give the procureur de la République time to obtain that the appeal be declared suspensive, the foreign national is kept in detention for a period of 24 hours (compared to 10 before January 26, 2024).
If the Conseil Constitutionnel does not reject the principle that foreigners may be deprived of their freedom despite a judicial decision to release them, in order to ensure the effectiveness of any appeal, it nevertheless considers that a duration of 24 hours is excessive and violates Article 66 of the French Constitution according to which: « No one may be arbitrarily detained (…). »
For reasons of legal security, the Conseil Constitutionnel postponed the effects of its decision to October 1st, 2026 and orders that, until that date (or until a legislative reform), the duration of detention awaiting an appeal be 6 hours instead of 24.