Paris teenagers have blockaded 16 schools in the city with burning rubbish bins and makeshift barricades in protest against the alleged rape of a young black man with a police baton and other alleged police abuse.
A crowd of protesting students, some hooded and carrying flares, also marched on the Place de la Nation in eastern Paris.
Images on social networks showed some carrying a banner reading Vengeance for Theo, the name of the alleged victim.
A Paris school district spokesman said extra security measures were taken after 16 of the region's 103 high schools were blocked on Thursday, and 12 others were also disrupted.
The Paris police headquarters said officers are monitoring the situation but reported no arrests.
Four officers have been charged over the alleged violence against Theo last month, which prompted violent protests in poor suburbs around Paris.