Five police officers were injured, two seriously, and a partygoer lost his hand when security forces tried to break up an illegal rave of some 1,500 people in western France, local officials said on Saturday.
TV images showed gendarmes using tear gas and ravers throwing firecrackers, projectiles and petrol bombs as clashes broke out when around 400 police officers moved in an effort to disperse the party.
According to Emmanuel Berthier, police chief for the Ile-et-Vilaine area, a 22-year-old person lost a hand amid the "extreme violence". Clashes lasted for about seven hours, the national gendarmerie said on its Twitter account.
As of Saturday morning, about 1,000 people remain at a horse racing track near Redon in Brittany where the rave was held and officials said they hoped to regain control over the weekend.
"Those present were not there to party, but to fight with the police," Pascal Duchène, the mayor of Redon, told BFM TV.
(Reporting by Nicolas Delame and John Irish, editing by Mark Heinrich)
