Five others are believed to have died as they sought to park their cars under shelter, according to local authorities, while emergency responders said three others drowned in their car when it became stuck inside a tunnel.
Another victim drowned on the street in the resort city of Cannes as violent storms hit last night.
Heavy flooding along the Cote d'Azur, in France's southeast, saw the River Brague burst its banks close to the city of Antibes and sent deadly waves crashing into the nearby retirement home.
"Camp sites are under water, and two helicopters are circling to ensure the public's security, as some people are stuck on the roof of their caravans," said a spokeswoman for the fire brigade.
The Cannes mayor's office said an emergency plan was now in effect, involving the mobilisation of police, emergency responders and municipal services.
Forecasters at France's weather agency said the worst storms had now passed over the French mainland and were headed for the Italian coast.
