well that's always possible but most of the vintage French or Belgian theater poster are completely different then this one.
Mostly they have a few scenes depicted (of every act) , name of the theater company/performer , date, place, ...
theatre Frederic Achard is one of these typical performers and if you look at his posters its completely different then this one
I also found another silent movie poster in that same lot for the movie Bavu, so I would rather keep looking in that direction.
Scala is a typical (movie) theater name and found a few in Belgium and France , so that won't really help us a lot.