Outside school gates across France, students are protesting over classroom conditions, and on Monday a 15-year-old lost a hand after picking up a police grenade.
Larger demonstrations are expected on Tuesday, while some classmates returned to lessons.
The anger runs deeper than one week.
Students have blocked entrances at hundreds of schools since late September, citing absent teachers, packed schedules, run-down classrooms and buildings poorly suited to rising temperatures, among other complaints.
The education ministry said more than 400 of France's 3,700 high schools, known as lycees, had closed fully or partly by Monday morning.
In the Paris region, authorities expect 1/3 of the 468 institutions for students aged 15 to 17 to shut.
Dozens of teens demonstrated outside Turgot high school in central Paris as cars driving by sounded their horns. Some classmates walked into the building for class.
"We're missing our lessons to give you one," read a cardboard sign at the site, in the 3rd arrondissement.
Some students in Bordeaux, in the southwest, went back to class while others kept demonstrating with riot police present. Outside Gustave Eiffel High School, some protesters launched fireworks toward officers, who occasionally responded with tear gas, though the overall situation stayed calm, Agence France-Presse (AFP) reporters said.
Protests began on Sept. 17 at a lycee in Creteil, a suburb of Paris, backing teachers striking over shortages of staff and resources. They later spread nationwide, sometimes turning into vandalism that included wrecked bus shelters, torched school entrances and confrontations with security forces.
The education minister said 24 schools have been set ablaze or ransacked since the demonstrations began. Arrests have topped 5,000, and 85% of those detained are minors.
Protesters also accuse officers of using excessive force, and internal investigations have been opened into at least 3 alleged cases of police brutality.
On Sunday, Prime Minister Sebastien Lecornu laid out a schedule, asking local authorities to make it a priority to cover vacancies from lengthy teacher absences and open positions. He scheduled a Tuesday meeting with regional presidents to discuss revamping the nation's frequently run-down school buildings.
"When you have 14-, 15-, 16-year-olds who, at 9 am, are burning bus shelters or, perhaps even more seriously, the high school where they study, that raises the question of parental responsibility," she told the Europe1/CNews broadcaster.
Lecornu has said compensation under the draft law could be recovered from family allowances and housing benefits, with a minimum income threshold preserved. Sophie Binet, who leads the main CGT labor union, blasted the plan as a "populist announcement" and warned it would "end up targeting the most vulnerable families."