Their cases are passed between institutions and the process can take months. In the meantime, they risk sleeping rough, being arrested or even deported before a final decision is made.
The recent police eviction of hundreds of youths occupying a Paris theatre has thrown a spotlight on this national challenge.
"We are not criminals, nor drug addicts. The only thing we are asking for is shelter, education and access to health. How can this be bad for France?" said Hamadou, a 16-year-old from Guinea who was among those evicted.
Each year, around 8,000 undocumented migrant minors arrive in Paris alone. Only about 2,500 are officially recognised as underage and immediately taken into care, according to Mayor Anne Hidalgo.
For those caught in administrative limbo, options are limited. Some, like Hamadou and 500 others, occupied La Gaîté Lyrique theatre in central Paris from 10 December 2023, before being forcibly removed by police on 18 March.
"I was so frightened, I could not find any sleep that night, before the police evicted us," Hamadou told RFI.
"The policemen, a hundred of them, looked like they were geared up for war with their shields, helmets and batons. Up till the last minute, I was convinced that they would never use force, that the Paris municipality will come to the rescue with news of lodgings for us."
Most of the youths at Gaîté Lyrique come from former French colonies in Sub-Saharan Africa. Many find themselves in a paradox: French law guarantees protection for unaccompanied minors under the International Convention on the Rights of the Child – but proving they qualify for that protection is increasingly difficult.
The X-ray bone examination is hardly ever carried out nowadays, the age assessment tests is mainly through interviews.
“This is problematic for us because it is not based on scientific evidence and it looks like the interviewer can decide whatever they choose to believe,” Hamadou said.
A hot potato
Mohamed Gnabaly, mayor of Ile-Saint-Denis and member of the Green party, told RFI that the Gaîté Lyrique case shows how different institutions bounce responsibility back and forth.
"It is fine as long as they remain invisible. The unaccompanied migrant minors became a problem because they were a sore sight right in the centre of the capital city," he said.
"And this fed the racist speech we heard about them within both the ranks of the government and the far-right."
Fousseni, from the Belleville park youth group which helped organise the occupation, said the delays and lack of shelter push the minors into impossible choices.
"By the time many have built up their case while trying not to get arrested, they have already reached 18," he said.
The Municipality of Paris brought the case to court in January. A court then issued an order on 13 February for the theatre to be evacuated within one month. When the city failed to act by the deadline, police chief Laurent Nunes said he had to intervene.
"The Municipality of Paris [owner of the theatre] did not contact me by 13 March. I had to take my responsibilities and put an end to this occupation which was disrupting public order," Nunes said on the TV programme C à vous.
"The Municipality of Paris asked for details on what accommodation would be given to the young people and how they were to be treated," he added. "This to me implicitly meant that the Municipality of Paris did not want security forces to intervene."
Caught in the clash
On 18 March, riot police used batons and tear gas to enter the theatre, pushing past human chains formed by activists, civilians and politicians.
"This show of force and attacking vulnerable black migrant minors is the first step of the military discourse the government and the far-right is currently using," Danièle Obono, an MP from the left-leaning France Unbound party, told RFI.
Police evict migrants from Paris theatre after months-long occupation
Belleville parc youth group reported that around 60 people were arrested, including minors and adult supporters. Ten were injured. So far, 25 minors have been issued deportation orders – a move the group says violates their legal rights.
"This is illegal because they are minors and are currently being processed by the ministry of Justice to prove that they are under 18," said Fousseni. "They cannot be thrown out of the French territory like used tissue papers."
Differing perspectives
Government officials say the situation is not as clear-cut. Minister François-Noël Buffet told parliament that the youths were mostly over 18. The government and far-right groups blamed them for damage and losses to neighbouring businesses.
Mayor Hidalgo defended the eviction, saying the situation had become unsafe.
"There are around 8,000 young undocumented migrants who arrive in Paris every year. Approximately 2,500 of them are recognised as minors and are immediately taken care of," she told France Inter.
"The situation was tensed, dangerous and very complicated."
Hidalgo said accommodation had been offered, but turned down.
Fousseni said the offer was in Rouen – too far from Paris, where most of the young people are enrolled in school, receiving healthcare and attending legal appointments. Only six accepted the placement.
Billionaire Elon Musk commented on the case on X, writing: "Another case of suicidal empathy... it will end civilization. Game over." He later added, "They're exploiting a bug in Western civilisation which is the empathy response."
Uncertain future
For Hamadou, the eviction had immediate consequences.
"I couldn't breathe. I escaped with only the clothes I am now wearing," he said. His suitcase, containing all the documents gathered to prove his age, was lost in the chaos.
Now, he and others like him try not to sleep in the same place twice, fearing police checks. They depend on charities for food.
"The greatest danger they now face is police violence," said Fousseni. "Police in Paris are preventing the unaccompanied migrants to sleep in the streets of the city. They are being pushed to the outskirts of Paris."
La Gaîté Lyrique management had supported the occupation at first, despite cancelling shows and taking financial losses.
"It is out of question to throw them out in the streets where it is freezing cold. We regret, however that we were taken over so suddenly," it said in a communiqué last December.
The theatre later criticised the lack of coordination between the Paris Municipality and the national government, which left the minors in limbo for three months.
For thousands of unaccompanied minors across France, the system remains opaque, slow and unforgiving – and the stakes are growing by the day.