Most of the victims in France drowned, while others died when hit by parts of buildings or trees and branches that were ripped off by the wind.
Nearly 900,000 people in France were without electricity. Rivers overflowed their banks in Brittany, and the threat of avalanches was high in the Pyrenees and the southern Alps.
In Paris, winds knocked over motorcycles and tossed garbage around the streets of the capital. Flights were delayed and some were cancelled at the two main Paris airports. A number of trains in western France were delayed due to flooded tracks.
Winds reached about 130mph on the summits of the Pyrenees and about 90mph along the Atlantic coast.
In neighbouring Spain, the Interior Minister said three people were killed by hurricane-strength winds and heavy rainfall that lashed the country's northern regions over the weekend.
Alfredo Perez Rubalcaba said the storm had been intense in certain regions and had caused the deaths of a woman in north-western Ourense and of two people whose car was hit by a falling tree in Arlanzon, just north of Madrid.
The national weather agency had warned that a violent cyclone depression had formed over the Atlantic Ocean and was to cross areas bordering the Bay of Biscay.
Portugal's home affairs minister Rui Pereira said a child had been killed by a falling tree in Paredes. The 10-year-old had been playing with a ball near a church while waiting to go to a prayer meeting.