This is the closest thing to a real Parisien patisserie you're going to find on this side of the North Atlantic short of getting on a plane and flying over to experience the real thing.
The quality here is outstanding, like real patissieres, they do not skimp on the butter, the most essential of ingredients, so if you are on a diet, you're out of luck. That also explains why their prices are higher than their competitors. Easily the best croissants, pastries and sandwiches you'll taste on the island of Montreal. I find they have strange hours, and have a tendancy to close early so try to aim for the middle of the day.
While their pastries and baked goods are the real star items here, I also have to add that their homemade sorbets are nothing to sneeze at either.