The strongest winds were recorded on the Breton tourist island of Belle-Ile, of 150 kilometres per hour.
Firemen across the two regions were called out more than 400 times, mainly to clear roads blocked by fallen trees and debris, emergency services said.
Coastal inhabitants in three departments of Finistere, Morbibhan and Loire-Atlantique were warned of storm-surge waves.
Southern England too felt the impact of the same weather system dubbed ‘Storm Katie’.
Winds gusting to 170 kph an hour forced the cancellation of around 150 flights in and out of Britain and left around 2,000 homes without power.
Heathrow airport reported around 130 cancellations with other flights delayed or diverted to other airports.
Some 20 flights in and out of London's Gatwick Airport were cancelled and another four diverted.
The service recorded gusts of 170 kph off the southern England coast, with winds of over 112 kph registered across the south.
A bridge crossing the River Thames in southeast England and the Severn Bridge which connects England and Wales were also closed, according to Highways England.
UK Power Networks said they were dealing with problems across Sussex, Surrey and Kent in southern England, leaving at least 2,000 households without electricity.
- with AFP