North-western France on Thursday braced for heavy rainfalls and winds of up to 150kmh as Storm Alex made landfall.
The French meteorological agency issued a red warning for the coastal department of Morbihan, in Brittany.
Four neighbouring departments have also been put on amber alert.
Météo France said that gusts of up to 150kmh were expected in Morbihan, adding that "many trees are will fall down and power cuts are therefore likely".
Other departments in Brittany can expect gusts of up to 140kmh and rainfall of up to 80mm.
The opposite end of the country, the south-eastern region of Provence-Alpes-Cote d'Azur, has also been issued an amber warning due to a "high-intensity Mediterranean episode", forecast to start on Friday morning.
"Expected rainfall accumulations during the episode are between 100mm and 150mm over large areas, with 200 to 250mm in some," Météo France warned.
Storm Alex will also impact southern parts of the UK on Friday with heavy rain and coastal gales of around 100kmh, ushering in a wet weekend.
"Parts of Wales, southwest England and eastern Scotland could see over 100mm of rain falling over the weekend, which is likely to lead to significant impacts from flooding, an enhanced risk of landslides, along with very difficult during conditions," the Met Office said.