I am not from Montreal and do not speak French but had a great experience at Sumac
-was a little confusing at first but if you intend to eat in (recommended), you tell one of the staff members you are eating in and they will you a number sign. Then when you order at the register you have to repeat that number and then you find a seat with your number sign up
-for Americans, think of Sumac as a fast casual restaurant (there are waiters but they are not taking your order; I do not believe you have to tip at the table although there is a tip jar at the counter)
-came in for lunch on a weekday and place was packed
-got the chicken Shawarma plate for $16 CAD. you get pita, hummus, pickled turnip, tahini and choice of 2 salads (went with cucumber and quinoa)
-food was light and fresh but delicious and flavorful at the same time. Was not heavy at all. Fresh
-ask for hot sauce
-restaurant is very bright and clean. Great place to chat as well
-waiters come by with water frequently. Good service
-would definitely come back. Less than a 10 minute walk from metro station
-note they are closed on Sunday and Monday
Overall a great eating experience