At least 16 people have been killed in and around the French Riviera after sudden heavy rains prompted flooding, trapping some in cars and in a retirement home.

Francois Hollande, the French president, said in a statement on Sunday that people were found dead in the towns of Cannes, Biot, Golfe-Juan and Mandelieu-la-Napoule in the southeast.

Heavy flooding along the Cote d'Azur in France's southeast saw the River Brague burst its banks close to the city of Antibes, sending deadly waves crashing into a nearby home for the elderly, killing three people.

A woman in her sixties also died on the street in the city of Cannes when huge storms hit the region on Saturday night, sending water and debris coursing down submerged roads in the famous festival town and in neighbouring Nice.

Another victim was found dead at an Antibes campsite, according to local officials.

"Some cars were carried off into the sea," said Cannes Mayor Davis Lisnard, describing water levels as reaching halfway up car doors and trees left uprooted on the city's main drag.

"We have rescued a lot of people, and we must now be vigilant against looting," he added, announcing that an emergency plan was now in effect to mobilise police, emergency responders and municipal services.

The areas worst hit by flooding were also the hardest to access, officials said, raising fears the death toll could rise again, while 35,000 homes were confirmed to be without power.

French rail company SNCF said around a dozen trains had to be halted with hundreds on board for the safety of passengers, while roads around Antibes were also flooded, according to French emergency services.

"Campsites 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.

Up to 500 tourists, including several British and Danish nationals, sought shelter overnight at Nice airport, while a Nice-Nantes football match was also interrupted by the downpour.

Source: AFP