You can find it in the larger Coops. I believe it is in the section with cereals or diet food, can't recall. It's a small plastic bottle with a green cap (or used to be a few months ago when we bought it). It is called in French Germe de Blé.
"Weizenkeim" is the German for wheatgerm. If not to be found in a larger Migros or Co-op, it's bound to be on the shelves of a health food shop - "Reformhaus".