From the street, the apartment building where Alaye Ba lives with his wife and four children has typical Parisian charm: a neat white facade, wooden shutters, lace curtains and a ground-floor cafe.

Inside is another story. A rickety wooden staircase winds through mildewed corridors that separate small apartments crammed with African immigrant families sleeping four, five or more to a room.

"I wake up at night sometimes because I'm afraid for my family. This building is not safe," said Ba, 46, a Senegalese immigrant. "If a fire breaks out here, we are prisoners. We will die."

On Friday, in a neighborhood not far from Ba's home, a building crowded with immigrants caught fire overnight, killing 14 children and three adults. Only four months earlier, 24 people died in a similar fire at a budget hotel where African immigrants lived.

The deaths triggered angry calls for action on behalf of the needy and cast light on the plight of France's growing immigrant population -- and the precarious conditions in which an estimated 2 million people live in Paris.

Some are asylum seekers placed in low-end housing while their residency requests are processed. Others are in France illegally. Many are families from Africa, Asia or elsewhere who have their papers in order and scrape by on low wages while waiting for placement in public housing, a process that can take years.

"Even in Africa, we might have been poor, but we didn't live like this," said Ba, who has lived with his family of six in a one-bedroom apartment since 2001.

The six-story building, across the street from the Finance Ministry, was supposed to be a stopover pending their application for a permanent state-subsidized apartment. City officials told the family to expect a six-month wait. It has been four years.

Like the building that burned down Friday, theirs was requisitioned by the government in 1991 to house immigrants. Such buildings are managed by associations that charge below-market rent and, according to advocacy groups, often turn a blind eye to maintenance failures and overcrowding.

"These are places nobody should live in," said Antoine Boutonnet of the French Red Cross. "When a building that is unlivable and unsanitary is packed with so many people, it's a tragedy waiting to happen."

Progress has been made under Paris Mayor Bertrand Delanoe. Since 2001, the city has refurbished 1,000 buildings deemed unsanitary, bought more than 27 budget hotels to serve as low-income lodging and built 15,000 public-housing units.

But the demand is enormous. France is the world's leading destination for asylum seekers, with 65,600 requests in 2004, according to the government.

In Paris, there are more than 100,000 outstanding requests for public-housing apartments.

For the Ba family and many others, waiting is the only option. Ba works as a window cleaner and his wife as a hospital cleaner. Together they earn about $2,200 a month. Rent is $390 a month and all they can afford.

"We have mice and cockroaches. There are leaks everywhere. Everything is rotting," said Aissatou Ba, 36. She pointed to crumbling plaster walls in their fourth-floor apartment, cracks in the ceiling and buckling linoleum floors.

Heat and hot water are powered by a rusting gas heater in the kitchen that regularly breaks down and has not been cleaned since they moved in, Alaye Ba said.

All four children, ages 2 to 9, share the tiny bedroom, where clothing is piled on the floor.

"There's no way out if there's a fire," said Aissatou Ba, opening curtains to reveal bars across the children's window. She and her husband sleep on the living room floor.

The only way out is to use the building's common stairwell, which has no fire extinguishers. Paris apartment buildings have no fire escapes.

Friday's fire at the seven-story apartment building in southeastern Paris started under the staircase. A small open window on the top floor created a wind tunnel that stirred an inferno up the staircase, prosecutor Jean-Claude Marin said.