Article L731-1 of the French Code governing the entry and residence of foreign nationals and the right of asylum
The administrative authority may place under house arrest a foreign national who cannot immediately leave French territory but whose removal remains a reasonable prospect, in the following cases:1° The foreign national is the subject of a decision imposing an obligation to leave French territory, taken less than one year previously, for which the period for voluntary departure has expired or has not been granted;2° The foreign national must be removed…