Montreal police arrested 21 people after a disruption at the city’s downtown francophone university Wednesday.

Police were called to l’Université du Québec à Montréal (UQAM) around 2 p.m. to respond to physical fights, according to CTV Montreal.

The clashes had broken out between those who favour a boycott of classes in protest of provincial budget austerity and those who wish to continue attending school.

Police could be seen holding what appears to be a Halloween mask as they walked a man in handcuffs to a police vehicle. They tweeted at 4 p.m. that the “intervention” was over.

Wednesday marked the first day of a 10-day injunction UQAM obtained allowing the school to stop student protesters from blocking entrances to buildings, as happened last week.

Two days after the injunction was obtained, masked intruders burst into a UQAM law classroom and demanded students join the boycott.

Several classes were also disrupted by masked protesters at the anglophone Concordia University last week ahead of a large march organized by a provincial student group.

Old tactic resurfaces

Classes were disrupted so often in 2012 that emergency legislation was enacted by Jean Charest’s Liberal government to address the issue.

The controversial law known as Bill 78 was passed in May, 2012 after widespread ‘Maple Spring’ demonstrations shut down many classes for months over a planned tuition increase.

That law required protesters to provide an itinerary to police eight hours in advance of any demonstration and included stiff penalties for those who blocked schools.

The law expired in July, 2013, but not until after it was used to arrest at least 19 masked protesters who moved from room to room emptying classrooms at UQAM by banging on pots and pulling fire alarms, in August, 2012.

The Liberal government fell to the Parti Quebecois the following month. The PQ then became the target of protesters after it said it would raise tuition three per cent.

The Liberals were re-elected to a majority government just over one year ago under premier Philippe Couillard. His government’s recently tabled budget aims to cut costs in order to reduce the gross debt that sat at $197.1 billion one year ago, which was the highest per capita in the country.

With a report from CTV Montreal’s Rob Lurie and files from The Canadian Press