At least 13 people have been killed and six are missing after violent storms and flooding have hit southeast France, officials said.
Three elderly people drowned when their retirement home near the city of Antibes was inundated with floodwater.
Another five people are reported to have died as they tried to park their cars under shelter and became trapped.
France’s President Francois Hollande has thanked rescuers and expressed the “solidarity of the nation”.
Francois Hollande and Interior Minister Bernard Cazeneuve are due to visit the affected regions.
Heavy rain hit the French Riviera, which lies on the Mediterranean coast and borders Italy, on Saturday evening, October 3.
The city of Nice is estimated to have received 10% of its average yearly rainfall in two days alone.
The river Brague burst its banks, sending water coursing into nearby towns and cities. Social media pictures showed water gushing down the streets of Cannes.
“Some cars were carried off into the sea,” said mayor Davis Lisnard.
“We have rescued a lot of people, and we must now be vigilant against looting.”
“We have lived through an apocalyptic situation that we have never experience before,” tweeted Eric Ciotti, President of the Alpes-Maritimes department.
The main highway through the area has been closed, trains halted and hundreds of tourists sought shelter at Nice airport overnight. Around 27,000 homes are without power.
Some concertgoers attending a show by rock legend Johnny Hallyday at a venue in Nice had to sleep overnight there after becoming stranded.