Right now there are not that many German options in Montreal.
There is Checkpoint Charlie on St. Laurent that opened a few months ago - no idea how good it is. (4433 Saint Laurent Boulevard)
Like I wrote last week in another thread there is Suzys bakery in Pierrefonds that has some German dishes also that you can eat there - I only tried her baked goods so far and they were great. (15450 Boul Pierrefonds)
Boucherie Atlantique have some meals as well with a small counter where you can eat.
(5060 Chemin de la Côte-des-Neiges)