The march was declared illegal because organizers didn't provide authorities with a route in advance of the demonstration.
Police, however, said they still allowed the march to proceed on the condition the protesters keep the peace and refrain from any acts of vandalism.
The peace was shattered about an hour into the march when riot police moved in to shut it down.
During the ensuing confrontation police say one demonstrator and one passerby suffered minor injuries, one police cruiser was vandalized, and one protester was arrested for assaulting police.
Similar demonstrations were staged in both Montreal and Quebec City earlier this week to protest the Quebec government's austerity policies.