One police officer has reportedly suffered burns, while five protesters were taken into care with minor injuries.
Police have clashed with protesters in France's western port city of La Rochelle, where demonstrations have been taking place against plans to construct plastic-coated artificial water reservoirs.
Roughly 4,000 demonstrators took to the streets, but the peaceful marches turned to unrest with shop fronts smashed and vehicles set on fire.
Officers attempted to break up the marches by constructing barricades, throwing tear gas canisters and discharging water cannons.
At least six people were arrested.
Controversial 'mega-basins'
Protesters in La Rochelle are demonstrating against a project which will see the construction of so-called 'mega-basins', which are plastic reservoirs that will extend over several hectares.
Several basins of this type were installed in France following the drought episodes of summer 2022, notably in Sainte Soline where environmental activists and NGOs opposed them.
These immense reserves are capable of containing the equivalent of 300 Olympic swimming pools or around 700,000 m3 of water.
But critics say the mega-basins are a non-permanent solution and risk depriving the surrounding ecosystems of the water necessary for their maintenance while slowing down the reconstitution of the soils which takes place during the winter period.