Well, I'm certainly learning a lot of stuff today. I didn't know garderobe was used in English and German.

It's pretty self explanatory in French with garde meaning "keep" and robe meaning "dress." So it is a place to keep dresses - a closet. It is pretty much the only term we use for a closet in Québec. Well, apart from saying the word closet with a French accent, which the language police abosolutely hate.