On November 19, the teenager named Thomas died after being stabbed at a festival in the Drome department.
Between 50 and 100 right-wing activists took to the streets of the Monnaie quarter in Romans-sur-Isere on Saturday night, demanding justice for Thomas, local broadcaster reported. Some of them overturned trash cans and set fire to containers.
About 120 law enforcement officers observed order at the protest, the report read. The demonstrators started throwing stones and firecrackers at police forces, after which 20 people were detained, with three of them suffering minor injuries.
The November 19 incident, in which eight other people were injured as well, caused a wave of shock in France, with the right-wing groups calling it a deliberate attack on white people.