image copyrightFrench policeimage captionAuthorities and partygoers blamed each other for the violence
A reveller had his hand blown off as hundreds of police attempted to break up an illegal rave in western France, officials said.
About 1,500 people were at the rave at a horse racing track near the town of Redon.
There were "very violent clashes" lasting seven hours after police intervened, the local prefect said. Five police officers were injured.
Authorities and partygoers blamed each other for the violence.
The event had been organised on social media and local authorities had banned it from going ahead.
Prefect Emmanuel Berthier said people attending the rave "had an objective, to confront the forces of order" and accused them of throwing petrol bombs, large metal balls of the type used in the French game of boules and breezeblocks at officers.
Event organisers said the police had chosen to fire tear gas rather than negotiate with them.
"Tear gas and stun grenades rained on the crowd who only wanted to party," one organiser told AFP news agency.
image copyrightBrittany regional government
A 22-year-old man lost his hand in the violence, prosecutors in Rennes said. An investigation was under way to determine the cause of his injury.
There were five arrests, police said.
The rave was held in memory of Steve Maia Caniço, a 24-year-old man who drowned in the Loire river in Nantes in 2019 after police raided a concert during a music festival.
His body was found more than a month later. Protesters in Nantes say the police intervention then was disproportionate.
In January about 2,500 people attended a rave in Brittany beginning on New Year's Eve and lasted 36 hours before police shut it down following clashes.