Watch: Fires and blockades as students stage school protests across France

Four-hundred-and-forty people, mostly minors, have been arrested and 76 injured as a wave of school protests over overcrowded classes and teacher shortages spreads across France, officials say.

The demonstrations began in Paris last week but have escalated to cities including Dijon, Lyon, Strasbourg, Lille and Marseille, with teenagers blockading their schools for days.

Education Minister Édouard Geffray said while some of the students' demands were legitimate what worried him was the violence.

He spoke of one young man having lost the use of part of his hand after firing a mortar firework. The dozens hurt since the start of protests included both pupils and staff, he said.

Secondary school students' union USL says as many as 400 of France's 3,700 lycées for 15-18 year-olds have been blockaded and it has called for further action on Thursday, including at universities.

Firefighters were called out in Strasbourg after bins were set alight outside a school, while in Dijon police used tear gas to disperse dozens of students, French media reported on Wednesday.

On Tuesday alone, at least 10 teachers and several students were hurt, according to the education minister, who added that one teacher had been beaten up.

Geffray singled out the radical left party La France Insoumise (LFI - France Unbowed) for stirring up trouble.

The LFI mayor of northern Paris suburb Seine-Saint-Denis, Bally Bagayoko, who has praised the protesters, has been criticised for suggesting that in some cases "violence can be legitimate" when a teenager is faced with riot police firing so-called "flashballs".

"Every time we try to express ourselves we get tear-gassed, they don't try to understand us," students at the Paul-Éluard lycée in Saint-Denis told France Inter radio. "When we try to talk about our rights, they tear-gas us, they hit us."

For days students have blockaded the lycée in Saint-Denis, and part of the school gate has been torn down.

Bagayoko was pictured on Monday dancing with protesting students outside the school and singing the Marseillaise with them, prompting Valérie Pécresse, the conservative head of the Île-de-France region that includes Paris, to demand he pays for some of the damage.

Students carried out a blocking protest at a secondary school in Lille

Reports from several cities have spoken of protesters hurling projectiles at police, who then responded with tear gas and sometimes batons.

One student suffered a serious eye injury near a school in Tours on Wednesday, amid unconfirmed reports he had been hit by a flashball fired by police.

There were further arrests on Wednesday in Nancy in the east and the Gironde region in the south-west. A teacher was left in shock on Tuesday in the northern city of Lille, where he was reportedly attacked after trying to ring the fire brigade to report a burning bin.

One 16-year-old female student said they were trying to deliver a message.

"We're not here to smash everything up for no reason," she told AFP news agency. "We're here precisely to say that the education system is completely broken. There are 34 of us in each class, and it's just not feasible. The teachers are overworked."

Ryad Rani, president of the USL, accused the French government of "repression" and police of using excessive force.

When pressed on the police response to the protests, which has come in for criticism from some politicians, Interior Minister Laurent Nuñez said it had been "carried out in an extremely proportionate manner".

French students blocked the entrance to a school in Paris

The movement began last week in the Île-de-France region. As it began to spread, Prime Minister Sébastien Lecornu warned that any escalation would be "irresponsible".

Students' union USL has now called for a large national protest on 6 October.

Tuesday's protests coincided with nationwide walkouts by unions representing teachers, hospital staff and civil servants to protest against issues including low wages and working conditions.

Nuñez said the broader public sector protests, with at least 200,000 participants reported, mostly went without incident.

French PM warns against escalation of school protests after 164 arrested