MONTREAL -- A history lesson on racism and the use of the "n-word" didn’t go quite as planned this week at St. Thomas High School in Pointe-Claire.

Speaker and actor Omari Newton was part of a series of lectures presented by Overture with the Arts that were made this week at the Lester B. Pearson School Board as part of the board's anti-racism week.

But it wasn't a student who caused the trouble -- it was a teacher.

As more than 100 students watched the online Zoom assembly on Thursday, a teacher started berating Newton and accosting him with profanities, said the organization doing the lectures.

“To hear an educator use such incredibly vulgar and profane language in front of children attending a large online assembly was shocking and upsetting,” a statement issued by Overture with the Arts said.

The presentation is called "Unpacking the N Word" and it includes a series of slides depicting some words and images that have historically been used to demean Black people. These include the book Uncle Tom's Cabin and its fictional slave Uncle Tom, who became synonymous to many Black people with servility and self-hatred.

Other images in the presentation include Uncle Ben's and Aunt Jemima, products that have used depictions of black people based on racial stereotypes.

But it was a Quebec book that sparked the teacher's reaction. Newton brought up a book called White (N-word) of America, by Pierre Vallieres, and said he rejects the notion that oppression faced by French Canadians around the time of the FLQ is comparable to that faced by Black people over time, including slavery.

The teacher then swore at Newton, calling him a profanity in French.

“It wasn’t a racial slur that he said,” Newton told CTV News.

“But I will argue that a white man interrupting a Black man after numerous requests from administrators to stop during an anti-racism presentation, a year after a viral video of students in blackface [at the same school board] went viral, is a form of, in my opinion, at the very least, unconscious bias.”

The teacher in question has not been named.

In a statement to CTV, the Lester B. Pearson School Board said the teacher's comments were “inappropriate and disrespectful and that the board is addressing the matter through appropriate channels.”

It did not say what those channels might be. The president of the Pearson Teacher Union did not respond to requests for comment.

Omari Newton said he would be willing to have a supervised discussion with the teacher. He also said he plans to continue talking to students about why systemic racism needs to be called for what it is.