About 200 protesters held a noisy demonstration during the lunch hour in downtown Montreal.
The protesters, members of about 100 groups including taxi drivers, women's groups, and students, were assembled as part of what they called the Main Rouge (Red Hand) coalition.
Their goal was to encourage the government to increase social spending, and to go after tax evaders.
The taxi industry was also represented. They say their situation is similar; they contest Uber's claim that it pays taxes.
Just two blocks away, Uber supporters marched to demand the government create regulations that will allow them to remain viable in Quebec.
With the recent release of the Panama Papers, about half of the protesters moved into the nearest branch of the RBC, the only Canadian institution linked to tax havens .
Documents leaked to dozens of media groups worldwide show RBC and its subsidiaries used Panama's Mossack Fonseca law firm to set up more than 370 shell companies.
They blew horns and whistles for about half an hour before being herded out by the Montreal police tactical squad.