A few years ago I had dinner at the Mozza in the west-island and recently I have had lunch several times with my mom at the location on McGill College (near the corner of St. Catherine). They are right in the center of downtown and are a good bet for a gluten-free meal. They have a separate gluten-free menu and while there is a chance of cross-contamination I found them very knowledgeable each time I was there.
The last time I was there I had olives, truffle fries (fried in a dedicated fryer) and a salad for lunch on their patio. Overall, this is a good place for a decent priced lunch right downtown and all their salads have been good.
Mozza
Accommodates gluten-free: Yes
Gluten-free menu: Yes
Price: $$
1251 Avenue McGill College, Montréal, QC H3B 2Y4