Hundreds of French high schools were shut on Tuesday as teachers’ unions joined a student-led movement demanding more money for education that has spread across the country and sometimes turned violent.

Around 256,000 people were taking part in demonstrations, including 56,000 in Paris, according to the Interior Ministry, with police using tear gas to disperse crowds in some locations. Nearly 500 people were arrested, bringing the total to more than 6,500 since Sept. 28, while 43 police officers were injured, the ministry said.

The protests, calling for smaller class sizes, building renovations and a reform of the system that allocates university slots, started in the Paris region in September before unexpectedly gaining steam last week.