Lashed by storms Xaver, Dirk and Ulla, Brittany has had more rainfall than at any time since 1959 and the country as a whole has had 15-20 more days of significant rain than normal, the Météo France weather-watchers report.
"This exceptional rain, combined with flooding by the sea during high tides of January and February, have caused serious flooding," Météo France said.
The storms were caused by an anticyclone of the Azores and a deeper than average depression off Iceland, meaning that north-west France was regularly hit by storms that had an even more severe effect on Britain, which had the most rainfall since records began in 1910.
The most severe storm was Ulla, which hit western France on 14-15 February with winds of over 150 kilometres per hours on the coastline.
A state of natural catastrophe, which opens the way for govnerment aid, was officially declared on Saturday for several parts of the country hit by floods, mudslides and coastal flooding in December and January.
The areas affected were parts of Brittany and Pyrénées-Atlantiques in the west, Alpes-Maritimes and the Var in the wouth-eaast and Normandy and Pas-de-Calais in the Channel coast.
Despite the storms, the winter's temperatures were exceptionally mild.
Temperatures were 1.8°C higher than average, only a little lower than the record set in the winter of 2006-2007.
The report is provisional, official results will be published on Tuesday.