The "one-in, one-out" UK-France treaty, which came into force on August 6, 2025, allows for the UK to detain and deport people who enter the country via irregular means. In exchange for Paris taking these asylum seekers back, London will admit an equal number of asylum seekers who apply for asylum in France and are approved to come to Britain. The agreement aims to stem the number of small boat Channel crossings.

Since the agreement was signed, four people were readmitted to French territory. An Indian man was the first person to be deported from the UK on September 18. An Eritrean and an Iranian were deported the next day, on September 19. A fourth person was deported a few days later, on September 23, according to the French Office for Immigration and Integration (OFII). 

In accordance with the “one-in, one-out” rules, London recently welcomed a family of three, including a small child.

What happens to people sent back to France? 

·       Three days of emergency accommodation

Migrants are sent back to Paris on passenger flights. After landing at Paris Charles de Gaulle Airport, the association SOS Solidarité offers them three days of emergency accommodation.

"We provide them with housing, physical and psychological check-ups, clothing, internet access, and a SIM card if they want to contact their families," said the association.

·       Transit sites 

The migrants are later transferred to various facilities, such as CAES centers. These are reception centers which offer temporary accommodation and aim to evaluate an asylum seeker’s administrative situation. The migrants learn about their rights in these facilities and begin the administrative process to try to regularize their status.

Didier Leschi, the director of OFII, told InfoMigrants what the state expects of migrants sent back by London: "They will first be encouraged to accept voluntary return assistance."

This form of assistance aims to persuade foreigners to leave France to return to their countries of origin. If a person agrees to return to their country of origin, the French government offers them a return flight and a sum of money for reintegration. 

Read AlsoVoluntary return from France: How does it work?

·       Voluntary return, asylum proceedings, or an OQTF (obligation to leave French territory)

"Submitting an asylum application will be possible, given that you qualify," said Leschi. The Dublin Regulation stipulates that the first EU member state that migrants set their foot in is the one responsible for processing their asylum application. Among the migrants returned to France, there are therefore potentially "Dubliner" migrants who cannot apply for asylum on French soil.

Those who refuse voluntary return assistance and do not qualify for asylum may be subject to an OQTF (obligation to leave French territory). They will then have 30 days to leave French soil on their own, before being placed in a detention center from which they face deportation.

Yet exceptions exist. While France is not expelling people to Afghanistan for the time being, "it is implementing voluntary returns to Kabul, and the situation may evolve," said Leschi. "Germany authorizes deportations back to Afghanistan, and the European Commission is considering amending the Return Directive," he added.

The European Union is tightening its migration policies, including a revision of the Return Directive, to accelerate and increase forced deportations. Several European states, such as Germany, Austria and Italy, aim to allow the return of Afghan and Syrian asylum seekers to their countries of origin, despite the return of the Taliban in the former and the fragile political situation in the latter.

How do authorities select the migrants to be deported to France? 

The selection criteria remain unclear. The Home Office said that anyone who crossed the Channel without applying for asylum, or whose asylum application was deemed "inadmissible," can be deported to France.

For the Home Office, an “inadmissible asylum claim” means it has been determined that someone has traveled through a safe country to reach the UK. They might have a connection to a safe country, including previously claiming asylum there, or could have reasonably been expected to do so. In other words, anyone who left the French coast is potentially deportable to France, which is considered a safe country.

The selection of migrants is currently being contested by the British justice system. The deportation of certain foreigners has been halted by judges in some cases.

Other cases may also be blocked by France. London sends proposals for "candidates" to the French authorities, in the hope they will be approved, a source told the French digital newspaper Mediapart. According to the same source, "around fifty cases are sent per week to the French authorities, who check whether the people can be readmitted, based on certain criteria."

The main criterion is security, said Leschi. The French authorities try to ensure that the person returning to France does not represent a threat to the population.