Brilla says she told the officer he was wrong, adding that when she started filming the interaction on her cellphone, the officer said he had only wanted to check if the women had proper bells and lights on their bicycles.
Ontario women have had the right to go topless in public since 1996.
A post on Facebook says people of all genders are invited to attend -- revealing as much or as little of their torso as they feel comfortable with -- to support the right of women right to be topless in public.