At Concordia University, some students on strike erupted into two classrooms, yelling at some students to leave.
In a video captured by Alex Bailey, a photographer for the school newspaper The Link, some students are seen yelling "Get the f--k outta here" to one of the students who barged into the classroom.
CBC has blurred the faces of those appearing in the video.
Concordia University had cancelled classes that day — but only those belonging to faculties where students voted to strike.
In one instance, the protesters barged into a classroom where some students belonged to a faculty that voted to boycott class.
At least two students in the classroom told CBC Montreal that the classroom contained a few students who belonged to faculties that were on strike that day.
They said the altercation made the mood very tense, and the professor ultimately cancelled the class.
Listen to Daybreak with host Mike Finnerty on CBC Radio One (88.5FM) at 7:15 a.m. to hear from students who witnessed the incident.
"There was foul language, some pushing and shoving and eventually the strikers left," said Chris Mota, spokeswoman for Concordia University.
"We are respectful of an individual's right to strike, we will not accept or tolerate that kind of a disruption. It really is completely inappropriate and it's nothing more than bullying."
Police were called in, but by the time officers arrived, Concordia security guards had the situation under control.
Bathroom graffiti at UdeM
Meanwhile, Montreal police are investigating an incident at Université de Montréal, after graffiti was found painted in a women's bathroom.
The messages targeted the spokeswoman of student union ASSÉ and were hateful in nature — alluding to sexual assault.
"These threatening comments attempt to instill a climate of fear to keep us quiet," read a statement from l'ASSÉ's women's committee.
University officials contacted police to conduct an investigation.