The Olympics Is Transforming Their Neighborhood. And Kicking Them Out.

The building, once a warehouse, apartments and offices, is a temporary home — with one shower — for 60 adults and children. On the ground floor, rats sprint under plastic chairs and parked baby strollers. The stench of damp clothes and clogged toilets overpowers the strong scents of tomato and spices from the makeshift kitchenettes on upper floors. In the inner courtyard, laughter echoes as children scoop up giggling babies and gently swing them skyward.

This is a so-called squat in Seine-Saint-Denis, a suburban area east of Paris that at one time was an industrial district. Now, it is a place with trendy cafes and high-fashion houses, as well as abandoned factories and spaces like the warehouse, which have become unauthorized housing for homeless people and immigrants.

Mariam Komara, 40, an undocumented immigrant from the Ivory Coast, has lived there since last year. The other day she was getting ready to go to court to argue that she has the right to stay.

“It may not be ideal, but it’s the best I have, and it’s a safe place to sleep,” she said one recent evening.

Soon, though, Seine-Saint-Denis will become the thumping heart of the Paris Olympics — with housing for thousands of athletes in the nearby Olympic Village — and ground zero for one of France’s central dilemmas.

Hundreds of thousands of immigrants have arrived in France in recent years, and nowhere is this more true than in the gritty suburb nestled in the shadow of the City of Light. Roughly a third of the more than 1.6 million people living in Seine-Saint-Denis are immigrants — the highest percentage in the country. The influx has strained the housing stock, and the government.