On Friday, a 17-year-old was arrested on suspicion of attempted homicide after protests in Belfort, north-eastern France, where a police officer was targeted.
At least 65 staff members have been injured in the unrest, the education ministry said.
In the Paris suburb of Pantin police charged at protesters and made arrests after projectiles where thrown at officers.
Meanwhile, in Strasbourg tear gas was deployed as police feared conditions would become more hostile, according to the Reuters news agency.
Rubbish bins have also been set on fire in Rennes and Paris.
“As far as we’re concerned, we’ve won – our school is closed this morning,” Lola, a 16-year-old protester, told the AFP news agency on Friday.
She said police actions had made things worse.
“It makes us even angrier – the police have no right to hit us or use tear gas on us,” she added.
In Marseille, fireworks were thrown at police and teachers were also inadvertently splashed with petrol at a school there, officials said.
“Significant damage” had been done to school facilities, the education ministry said.
Nelson Mandela high school in Nantes had suffered more than €2m (£1.7m) damage, according to the regional government.
