Clashes have erupted between strikers and police in nationwide demonstrations that have gripped France for weeks.

Officers have fired tear gas, and riot police officers have been deployed to face off thousands of demonstrators during a one-day strike.

Firefighters have been forced to extinguish blazes across the country, and confrontations have unfolded in Paris and Lyon, as at least 600,000 took to the streets.

The protests follow demonstrations over living costs, public services and education that have triggered the worst civil unrest France has seen in years.

Education minister Edouard Geffray condemned the “criminal behaviour” after people threw fireworks that started a large fire at a high school near the city of Toulouse in the southwest on Thursday morning.

High school students and other demonstrators had earlier faced off against riot police in Paris as they blocked a street with rubbish bins.

A protester holds a smoke flare near the Triumph of the Republic sculpture at place de la Nation…