At least one person is in a critical condition and several others injured in clashes between French police and protesters opposed to a water reservoir.
Police fired tear gas to repel some protesters who threw fireworks as they approached the construction area in the western rural district of Sainte-Soline.
At least three police vehicles were set alight.
Two protesters were seriously hurt, including one who is in a critical condition after suffering a head injury, as well as 16 police officers, the local prefecture said.
One officer was evacuated by helicopter.
Thousands of protesters had converged on the site of the planned reservoir, where a similar protest last October also turned violent.
The protesters, who staged the demo despite a ban on gatherings, are opposed to a large water reservoir for farm irrigation.
They were met by around 3,200 police officers, said Interior Minister Gerald Darmanin, who blamed far-left groups for the violence.
The heavy police presence included helicopters and squads riding quads.
France’s worst drought on record last summer sharpened the debate over water resources in the European Union’s biggest agricultural sector.
Supporters say artificial reservoirs are a way to use water efficiently when needed, while critics - who call them “mega-basins" - argue they are outsized and favour large farms.
The protest over the irrigation project alongside weeks of demonstrations in France against the raising of the pension age without a parliamentary vote.
More than 300 were arrested during protests this week in Paris and other major cities across France, with some marred by violence.
The King’s state visit to France, which was due to begin on Sunday, has been postponed amid the ongoing violence at French president Emmanuel Macron’s request.
