Initial investigations suggest gas was the cause of the blast, which destroyed the small building and seriously damaged two neighbouring buildings.

The woman had been listed as missing after the blast at around 8am (0700 GMT) in the Chartrons district of the western French city.

Firefighters said they found her body under rubble at around 4pm.

Her partner, the 89-year-old man, had been fighting for his life in hospital before his condition later improved, according to officials.

A second person initially named as missing has since come forward.

So far nine other people have been identified with minor injuries following the blast.

A member of the dog-technical team arrives at the site of the explosion. Photo: AFP

About 70 firefighters were on the scene.

Emergency services used sniffer dogs and equipment to clear the debris in their search.

The explosion destroyed a car park and garage on the ground floor and lodgings on the floor above.

The windows of several nearby shops were blown out by the force of the blast.

Lucie Perrouault, 21, said she was scared when the windows “exploded”.

“The glass from our window was blown onto us, we stepped on glass and my boyfriend was injured,” she said.

The large explosion destroyed the building as well as two neighbouring ones in Bordeaux' Chartrons district. Photo: AFP

Mael, 38, said she “was sleeping and I heard a great 'boom' — my bay window exploded”.

“I went outside and saw that an apartment had been blown up”.

While gas supplies to the district have been cut, “we don't know yet whether it was the gas network or canisters” that caused the explosion, said Eric Destarac, a spokesman for gas distribution company Regaz.

Firefighters recovered some gas bottles from the garage, he added.