The Gaîté Lyrique theater has been a jewel in Paris’s glittering cultural scene since the 19th century. It once hosted the operettas of Jacques Offenbach and performances by the Ballets Russes.

This season, though, its most talked-about drama has been generated by more than 300 homeless immigrants who are camping in the venue, sleeping on its floors at night and demanding that the French government provide them with real housing and other benefits because, they say, they are under 18. This is a crucial bureaucratic hurdle in France: If they are legally recognized as unaccompanied minors, they become eligible for housing and other government aid.

The Belleville Park Youth Collective, a Parisian group that includes immigrants and nonimmigrant left-wing activists, is organizing the occupation. Since 2023, they have staged similar occupations in other, lesser-known venues. Organizers say their actions have pressured city officials into finding 800 shelter spots for youths.

But the city government says it has no shelter space left. And it has made a preliminary determination that many of the migrants are not the age they say they are. That has left many of them in limbo while they pursue their appeals in court.

As signatories of the United Nations Convention on the Rights of the Child, European countries must give special protections, including housing, to immigrant minors. And the question of lying about — or being unable to prove — a birthday has become a flashpoint as anti-immigrant sentiment helps fuel the rise of far-right parties across the continent.

“This is a huge issue in Europe,” said Ulrike Bialas, a sociologist who has studied young immigrants in Germany, and is a research fellow at the Max Planck Institute for the Study of Religious and Ethnic Diversity in Göttingen, Germany.