Fire crews evacuated the block on Erlanger Street but were still fighting the flames. Many of those affected, took refused in nearby roofs.
The death toll from a fire at a residential building in Paris now stood at 10, said Paris prosecutor Remy Heitz, who added that investigators were favouring a "criminal" cause for the blaze.
Heitz also told reporters that a woman had been placed in custody as part of the investigation into the blaze.
The blaze in the French capital's trendy 16th arrondissement also left 27 people - including three firefighters - with minor injuries.
TRT World's Philip Owira reports.
People on the roofs
Some of those affected scrambled on to nearby roofs to escape the smoke and flames, and needed to be rescued by fire crews.
With landmarks including the Trocadero overlooking the Eiffel Tower, Paris Saint-Germain's home stadium the Parc des Princes, the picturesque Bois de Bologne and an array of upmarket shops and restaurants, the area is popular with tourists.
Fire service spokesman Clement Cognon said, "We had to carry out many rescues, including some people who had taken refuge on the roofs."
At approximately 0230 GMT (3:30 am local time), fire crews had finished evacuating the block on Erlanger Street but were still fighting the flames. Several surrounding buildings were also evacuated.
Around 200 firefighters were still at the scene in the early hours of Tuesday, battling the blaze and treating the injured.