Update 30/11: Aude and Pyrénées-Orientales residents are being told to stay at home because of a Météo France red alert for heavy rain and dangerously high river levels.
The severe weather warning is in place until 6.00 on Monday. About 300 people have been evacuated from their homes and spent the night in municipal halls.
Firefighters received 1,000 phone calls reporting flooded homes and blocked roads. Up to 17cm of rain fell overnight in Durban-Corbières in the Aude and 12cm in Torreilles.
The number of people killed in storms in the south of France has reached four - with another two people still missing.
Six departments were on orange alert by Météo France on Saturday: the Haute-Corse, Corse-du-Sud, Hérault, Aveyron, Aude and Pyrénées-Orientales.
All four of the people killed yesterday were in the Var - a man in his 40s in Cogolin, a woman in her 50s in Hyères and two other victims in La-Londe-des-Maures.
President Hollande spoke of "the nation's solidarity" towards those affected and thanked "all the elected officials and emergency services who have been working flat out".
He said everyone should follow the safety advice given by prefectures and Météo France.
The Hérault prefecture is urging residents to avoid travelling today unless essential - and to stay away from the coastal roads and paths.