Riot police fired tear gas to end repeated clashes on Tuesday among hundreds of migrants in Calais who launched their second attempt in two days to storm lorries bound for Britain.
The clashes between youths armed with sticks, rocks and knives broke out after a dispute over an alleged theft, police said.
Groups of 30 to 40 migrants were still roaming different parts of the port city on Tuesday night and continued to clash with rivals, said Gilles Debove, a police union spokesman.
The escalating violence prompted demands from police officers for guns, according to the local newspaper, La Voix du Nord.
The 15 local officers, who deal with minor crimes and are not usually called on to deal with migrants, are to get stun guns and guns that fire rubber bullets. But they have claimed those weapons are insufficient as the migrants – who are all trying to reach Britain and frequently try to jump on lorries to cross the channel – have become increasingly violent.