The windows of several fire stations were spray painted with the team's blue, white and red Wednesday in the run-up to the playoffs Thursday night when Montreal downed the visiting Boston Bruins 4-1.
Mayor Gerald Tremblay ordered a stop the practice Thursday and said a private company would be hired to remove what he called "graffiti." The mayor said the firefighters' union would get the bill, The Gazette newspaper reported.
The city and firefighters union have been in testy contract negotiations for the past few months, the newspaper noted.
Despite Tremblay's order, Montreal police announced Thursday patrol cars would be flying Canadiens flags during the hockey games.
The Bruins and Canadiens meet again at the Bell Centre Saturday night.