Here's a CBC report (video or text) about police dressing up as anarchists and trying to start a riot during the recent SPP protests in Quebec.
The boots of the provocateurs match those of the police, and the men fled behind the police line to escape. The police refuse to say who the men were, and no other protesters recognize them. You can watch the full union footage on youtube, which is where the CBC got the story from.
PS: I attended the associated SPP protest in Vancouver (I estimate 600-800 people were there) and took some photos. I hadn't heard about the SPP before. It hasn't been in the news, and thats one thing people are protesting about: the secrecy behind it. I still don't know the full details, but I don't like the idea of Canada putting ourselfs under the US homeland security umbrella.