High winds and waves are expected in six areas of Normandy and Brittany: Manche, Côte d'Armor, Finistère, Morbihan, Loire-Atlantique and Ile et Vilaine.
The local weather forecast predicts winds of up to 120km/h on Friday night inland and up to 140 km/h on the French Coast of Cornouailles.
On the Atlantic coast a rise in sea levels is expected, with a tidal coefficient of 84 for Saturday morning.
On Thursday the Vendée area, with its kilometres of rivers, was under water.
The town of Talmont Saint-Hilaire, near Les Sables d'Olonne, was suddenly inundated with 30 cm of water in its streets.
Dozens of roads were still cut on Friday and heavy rain could worsen flooding from rivers in Vendée, Brittany and Normandy over the weekend.