A lot of jokes start with the line “a man walks into a bar.” But in Canada, it’s a case of “a bar runs into a man.” Only this is no joke.

The bar Morrissey House in London, Ontario, has become the center of a gender discrimination complaint from an area man.

The man — who has not been named — complained to Morrissey House owner Mark Serre after the pub launched a new promotion.

The promotion offers a 13 percent discount on food to women on Monday nights. No discounts are allowed on alcohol in Ontario.

The discount was prompted by the debate about the pay gap between men and women doing the same work. In Canada, women get 87 cents for each dollar their male counterparts make — hence the 13 percent discount in the "Mind the Gap" promotion.

The complainant is threatening to take the pub to the Ontario Human Rights Tribunal. According to Serre, the complainant says differential gender pricing goes against basic human rights. It's making national news in Canada.

Serre is lucky to have help from Canadian human rights lawyer Susan Toth, who happens to be a regular at the pub. Toth says the complainant has an uphill task.

“There’s a couple of things to keep in mind,” Toth explains. “One is that not every differential treatment is actually going to be a violation of your equality rights. Because the courts have recognized — at least in Ontario — that there’s a difference between perfect equality and actual substantive equality. The idea being that in some cases, differential treatment is actually going to address a prejudice rather than actually aggravate it.”

Toth mentions a ruling by the Ontario Human Rights Tribunal in 2013 in a case against another pub, "The Barking Frog," when a man complained about women not having to pay a cover charge on Ladies’ Night.

“The courts are going to look at, has one group been historically advantaged or disadvantaged, and does the differential treatment perpetuate or aggravate some sort of a prejudice or stereotyping?”

“All the evidence shows — in the overall societal context — that women continue to be discriminated against in every aspect of their careers, their lives,” says Toth.

The Morrissey House has another promotion called Redhead Days, which runs for a week in September, when the pub gives a 15 percent discount to anyone with red hair. There have been no complaints regarding that.