At least 10 people have died after a blaze swept through an apartment block in central Paris in the middle of the night, a spokesman for the city's prosecutor told CNN Tuesday.
Paris prosecutor Rémy Heitz said earlier that the fire may have been started maliciously.
At least 37 people, including six firefighters, suffered injuries, fire service spokesman Clément Cognon said. One person was seriously injured.
Heitz said that one woman, who lived in the building, had been taken into custody, and an inquest has been opened. The 40-year-old woman was arrested in the road immediately after the fire, Heitz said. She has a history of psychological problems, he added.
Firefighters are still working to control the blaze on the top two floors of the eight-story building and searching for residents, Cognon told AFP, adding that the death toll could rise. He added later that there was a risk of collapse between the two upper floors.
The fire started at around 1 a.m. local time Tuesday (7 p.m. Monday ET) on the Rue Erlanger in the city's 16th arrondissement, and sent some residents fleeing onto adjoining rooftops.
"We had to carry out many (residents), including some people who had taken refuge on the roofs," Cognon said. As many as 50 people were rescued by firefighters, he later said.
Around 30 people were evacuated from the building using ladders. Two neighboring buildings were evacuated as a precaution.
Paris mayor Anne Hidalgo tweeted her sympathies after learning the news. "Paris is mourning this morning after the ferocious fire in a building in the 16th arrondissement. The toll is terrible," she wrote.
She and Interior Minister Christophe Castaner attended the scene early Tuesday morning. Speaking alongside Heitz and Castaner at an impromptu press conference, Hidalgo said the building was very difficult for fire ambulances to access, and had at least 50 apartments.
By 4 a.m. local time, the building had been cleared, although some 200 firefighters remained on the scene battling the blaze. As many as 250 firefighting personnel were mobilized during the operation, Cognon said.
Paris' upmarket 16th arrondissement is located west of the city center and features numerous notable landmarks, including the Trocadéro gardens, with their views of the Eiffel Tower, the Roland Garros stadium that hosts the French Open tennis tournament, soccer team Paris Saint Germain's home ground, the Parc des Princes, and, on its western edge, the sprawling Bois de Boulogne public park.