There have been violent protests in France after a young man demonstrating against a controversial dam project died amid clashes with police at the weekend.

Trouble was reported in Nantes and Rennes in Brittany, and at Albi where 21-year-old Rémi Fraisse was killed, near the site of the planned dam in southwest France.

His death has sparked a furious political row, with the Greens accusing the Socialist government of failing to take it seriously.

The local prosecutor said the protester died of wounds caused by an “explosion”.

“The medical examiner, on the basis of the lesions to the body that were found, can neither confirm nor deny that the origin of the wound came from an explosive device thrown from the zone where the police officers were taking refuge,” Claude Dérens told reporters.

Earlier about 2,000 people had protested peacefully against the Sivens dam project in the southwestern Tarn region.

Its promoters say it will benefit the economy and help farmers irrigate and develop crops.

Its opponents claim its economic benefits will be limited and the dam will destroy biodiversity.

One protester described events surrounding the young man’s death:
“Several explosive grenades and flash ball shots were fired. Next, our friend was on the ground. Apparently the grenade was stuck between his bag and his shoulder, it seems to have exploded there.”

The protester’s death is the first fatality at a French demonstration since the 1980s.

France’s Interior Minister Bernard Cazeneuve, while sending his condolences to the young man’s family, has condemned “unacceptable violence” by the dam’s opponents which have injured dozens of police.

The Greens, who left the Socialist government earlier this year, have called for a parliamentary inquiry.

The dead man’s family are reportedly preparing to make a formal complaint alleging murder.