The President offered condolences to the families of the victims and pledged government assistance to all those affected by the disaster.
Torrential rains hit the French Riviera, flooding rail terminals and motorways and leaving thousands of households without electricity.
The city of Nice is estimated to have received 10 percent of its average yearly rainfall in two days alone. The river Brague burst its banks, sending water gushing into nearby towns and cities.
Three elderly people drowned when floodwaters inundated their retirement home near the city of Antibes.
Others died trapped in their cars in tunnels and underground car parks as the waters rose.
The areas worst hit by flooding were also the hardest to access, officials said, raising fears the death toll could rise. About 27,000 homes remained without power early on Sunday, 14,000 of them in Cannes.
The Elysée palace announced on Sunday that victims of the flooding will receive help from the state under a French law that gives compensation to victims of natural disasters.
A tweet from the president’s office said it would be paid within three months.