Around 400 French schools are expected to stay closed on Friday to try to quell a series of violent student protests around the country.
The protests over dilapidated school buildings and teacher shortages began in the Paris region last month, but have spread around the country and turned increasingly violent.
Education minister Edouard Geffray told broadcaster France2 "a little over 400 schools and other educational establishments" would close on Friday.
Around 2,000 people have been arrested since the protests began, according to justice minister Gerald Darmanin.
"There is an active and violent minority (participating in the protests)... We're not entirely sure that they are even
high school students themselves," Mr Darmanin told RTL radio.
Students have set fire to schools and vehicles, including a fire engine.
Latest pictures from Toulouse's Lycee Deodat-de-Severac school on Friday showed bins on fire and police making more arrests.
Some of the worst violence on Thursday was in the southern city of Marseille, France's second-largest, where protesters started fires in at least two high schools, officials said.
Two teachers were accidentally splashed with petrol at the city's Victor Hugo high school, while at the nearby Saint-Exupery school, hundreds of young people forced firefighters to leave their truck before setting it alight.
Marseille's public transport system was suspended after staff were injured in the clashes.
The Nelson Mandela high school in the western city of Nantes was evacuated after it was set alight, according to mayor's deputy, Olivier Chateau, who told broadcaster franceinfo the fire was under control and there had been no injuries.
In northern France, there was violence at Lille's Baggio high school, where images showed riot police on the scene, fires on the street and people pulling down a traffic light.
More unrest took place in the Normandy city of Le Havre, where the facade of a school suffered fire damage; at least one car was torched in Strasbourg in the east; and riot police clashed with youths in Toulouse, in the southwest.
In the Parisian suburb of Saint-Denis, crowds of young people massed in front of a line of police. One student held up
a sign that read: "Can we explain ourselves without being teargassed?"
Thursday's clashes followed a series of deeply unpopular spending cuts announced by ministers in the 2027 budget earlier in the day.
France's intelligence agencies told ministers on Thursday that hard-left politicians initiated the campaign, according to a source close to the prime minister quoted by Reuters.
The unnamed source said officials pointed to "LFI [France Unbowed] and its proxies on the far left".
Read more on Sky News:
Arrest after RAF base incident
Flydubai plane hijacking latest
Ex-teacher jailed for indecency
LFI MP Louis Boyard dismissed the accusation, telling BFM TV the group "has always advocated non-violent demonstrations".
Ministers turned it into a political battle "by insulting and repressing high school students", he said.
Prime Minister Sebastien Lecornu held a crisis meeting on Thursday afternoon while French education minister Edouard Geffray said he would meet unions, parent associations and student groups on Friday.
Students have accused the police of using heavy-handed tactics, including the use of tear gas.
The government criticised the violence that broke out during some of the protests, but said difficulties in high schools should be acknowledged and addressed.
(c) Sky News 2026: Hundreds of French schools to stay closed after violent student protests
Flydubai captain Smit Machchhar 'could not let people die' as he describes fight to open cockpit door
Imran Khan supporters to be kept out of Pakistan's capital by shipping containers seized from 'distressed' lorry drivers
More than 4,000 deaths recorded in DR Congo Ebola outbreak
SpaceX flight led by first black female commander sets US speed record