The detention of a foreign national in irregular stay in a detention centre cannot be equated with imprisonment for various reasons:
- Purpose: the main purpose of a prison is to carry out a punishment. The purpose of detention in a detention centre is to ensure the effective return of persons who have been refused entry or residency in the territory. The foreign national is held to organise their forced return (identification, obtaining the travel document, booking a flight, etc.)
- Duration: the prisoner must serve a fixed sentence, which may be reduced through the various modulation possibilities. Foreign nationals in a detention centre can decide when to leave if they cooperate and provide the information required to organise their return.