Parents are livid after a workshop on bullying at a school on Montreal's South Shore devolved into profanity-laced insults and tears.

A student teacher at Pierre-Boucher Elementary School in Boucherville led an exercise in bullying that quickly went wrong, according to parents who spoke to CBC's French-language service Radio-Canada.

Several students were crying. It's completely deplorable that a teacher would authorize such a situation in her class. - Parent at Pierre-Boucher Elementary School

Without being told why, a 12-year-old boy was asked to leave the classroom by the teacher. His classmates were instructed to think of insults as part of the lesson.

After being called back into the classroom, the boy was met with a flurry of insults, ranging from "idiot" to profanity-laced taunts.

"There were no limits," one parent, who asked not to be named to protect the identity of their child, told Radio-Canada.

After each insult, students dropped a dictionary into a bin the boy was told to hold. The weight of dictionaries was meant to represent the weight of hurtful words.

The exercise ended after 15 minutes with several students in tears.

"The students who insulted the other student are also affected," said another parent, who also didn't wish to be identified.

Parents at Pierre-Boucher Elementary School say the workshop ended with several students in tears. (Google Street View) "Several students were crying. It's completely deplorable that a teacher would authorize such a situation in her class."

The school board, the Commission scolaire des Patriotes, confirmed the incident in an email to Radio-Canada, calling it "unfortunate," but declined a request for an interview.

In a letter to parents, the school board said there was help available for students who wished to talk about the incident.

The school board also said it had dismissed the student teacher, saying that the workshop was not authorized by administration.

Égide Royer, a psychology professor at Laval University, said the exercise showed a lack of judgment.

"We don't want to encourage young children to model aggressive behaviour," he said.