President Nicolas Sarkozy toured areas of western France that were hit by storms and flooding which killed at least 48 people, pledging €3 million to help victims.
Mr Sarkozy visited the coastal town of Aiguillon-sur-Mer, the hardest hit area of France where 25 bodies have been recovered after a dike collapsed, causing flooding that trapped many victims as they slept.
The government has declared a natural disaster, which will enable victims to claim compensation and free up insurance flooding claims and it has also announced it will seek European Union aid for the region.
Mr Sarkozy said there would be a detailed examination of the causes of the disaster, a plan to strengthen sea levees and emergency help for farmers.
Heavy rain combined with strong gusts of winds and high tides destroyed several Atlantic coastal sea walls along the western regions of Vendee and Charente Maritime at the weekend.
Many people woke to find their houses already flooded and several people told how they had to swim to safety as water poured in through the windows of their houses.
Victims driven out of their flooded homes were put up in temporary shelters and numerous injured were flown to nearby hospitals.
Initial reports suggested that the damage was caused by an unusual combination of extremely high winds, strong tides and an atmospheric depression which strengthened the sudden rise in water levels.
The French weather service Meteo France issued a red alert warning on Friday but there was no evacuation of coastal areas.
Transport Minister Dominique Bussereau denied that authorities had failed to take sufficient precautions but Philippe de Villiers, president of the Vendee local government, said building codes near the coast should be overhauled.
Dubbed 'Xynthia', the Atlantic storm crashed against the western coasts of France and Spain yesterday, bringing with it a band of severe weather stretching from Portugal to the Netherlands and inland as far as Germany.