Expansion of barn

Hello forum, I am new here and hope someone can help me. I live in Austria and still have an old barn in Germany. I bought this old building many years ago when I still lived in Germany. This barn has an upper floor where hay was stored in the past. Back then, the upper floor was a completely empty room under the pitched roof. Over the years, I renovated a lot of the building. Among other things, I separated part of the upper floor with a wooden wall and thus gained a small storage room (approx. 20 sqm). Then I moved away from Germany. Meanwhile, I use this room as quarters when I am in Germany. There is a small camp bed there, and I sometimes sleep there for a few days. Now I want to renovate this small room soon, wallpaper it, put in a few small pieces of furniture, and continue to use the room as a holiday accommodation. Meanwhile, I am having some thoughts about whether this is "legal". I never had a building permit for erecting the wall, although I always assumed that I did not need one for an internal lightweight wall. And what about if you occasionally stay there overnight, do you have to register that somewhere? Somehow this is certainly a "grey area", who can give me information about this? Regards, Maxe

I would rather say "where there is no plaintiff, there is no judge" - or "let sleeping dogs lie," if you now inquire at the building authority or something, someone might get 'stupid' ideas.......

No one in Germany will forbid you from sleeping in a barn for a few days, as long as it does not turn into permanent use.

Best regards
Dirk Grafe