Detention

Useful addresses in case of arrest and detention of foreigners:
If an undocumented migrant has been checked on the territory or upon arrival in France, he or she may be locked up. In order to find them, you must first distinguish between the different types of detention in France, and then call the different centres.

See here :
https://www.gisti.org/spip.php?article1811

The police may find that a person is in an irregular situation during an identity check. They can then take the person to the police station for an identity check (maximum 24 hours). If illegal residence is proven, the person will usually be placed in an administrative detention centre (CRA) for a maximum of 90 days, during which time the prefecture will do everything possible to deport him/her to his/her country of origin.
You can also request the assistance of a lawyer, who can help you to contest your detention and the decision to deport you.

Simply being without a residence permit is not a crime, and you cannot be held in custody just for that reason. But you can be placed in police custody (for a maximum of 24 hours, renewable once) if you have remained in France despite a decision to expel you, or for another offence.

During detention or custody, everyone has the right to ask for the assistance of a lawyer. If you do not have a lawyer, you can ask for one to be assigned to you (court-appointed lawyer). You also have the right to ask to see a doctor.

After detention or custody you can be placed in a detention centre to be sent back to another country. In each detention centre there is an association present to inform you of your rights and help you to enforce them. You can also ask for the help of a lawyer, who can help you challenge your detention and the decision to deport you.

The maximum length of detention is 90 days. But be careful, you have a very short period of time to react if you want to avoid being deported. You have 48 hours from the time you are placed in detention to appeal to the administrative court and contest the decision to expel you. If you want to apply for asylum, you must also do so during the first 5 days.

You will automatically be presented to the judge of liberty and detention after 48 hours. He will decide whether or not it is legal to extend your detention for another 28 days. At the end of these 28 days, the prefecture will ask for the detention to be extended. You will again be brought before the judge for a further 30 days, after which it is possible that the judge will order a further extension of 2*15 days.
If you have not been deported at the end of this 90-day period, you will be released.

It is therefore important that you seek legal support as soon as you are placed in detention.

You can also be placed under house arrest pending deportation. You will not be allowed to change your place of residence and you will have to report regularly to the police or gendarmerie. You will not automatically receive legal support from an association.

We therefore advise you to contact an association as soon as possible:
http://w2eu.info/fr/countries/france/contacts

Any foreigner arriving illegally in France by air, sea or rail at an airport, port or train station may be held for 26 days in a “waiting zone”.
He may apply for asylum with the help of an NGO.
Call ANAFE: Legal hotline Tuesday and Thursday from 10am to 6pm on 01.42.08.69.93.

ANAFE website: http://www.anafe.org/

For more information on administrative detention and on the different detention centres in France: https://www.lacimade.org/publication/rapport-2018-centres-locaux-retention-administrative/

[Translated with www.DeepL.com/Translator (free version)]