Montreal has a small Chinatown (or Quartier Chinois) that is east of most of the downtown hotels. From the Sheraton, it was about a 30 minute walk east (10-12 blocks) on Rene-Levesque, and then south 4-5 blocks on Jeanne Mance. In winter months, you can take the subway or a taxi.
Some of the Chinatown landmarks are being restored. There are many small stores and restaurants (Chinese, Korean, Vietnamese, Thai, etc), but none stand out enough to mention.
Of all things, my wife asked at one shop about where she could buy the lace curtain/valance material they had in the shop window. They gave (lengthy) directions to a fabric shop. I knew neither of us could find it, so I figured that was the end of it. Days later, we stumbled upon the place downtown without even trying, and we brought home several meters of fabric!
If you are walking to Old Montreal (see Journal entry) from the west side of downtown, Chinatown is worth a look.