Violence erupted when about 20,000 people demonstrated against an airport project near the city of Nantes on Saturday, leaving six riot police officers injured, reports Reuters.
Environmental activists have been protesting for more than a year against the government's plan to build a new airport for the west of the country, with some activists occupying the area by living rough in makeshift wooden cabins.
Police have tried several times in vain to evict the squatters and have had to contain many demonstrations.
The protesters, including farmers, locals and green politicians, argue the new airport will damage the environment and is a waste of public money during an economic crisis.
Read more of this report from Reuters.