Why do you think mystery is not an appropriate genre for this film?

The term "mystery " tends to be used differently in German than in English, where "mystery" primarily refers to crime literature. Supernatural events are only a peripheral area there. Although the German mystery genre often investigates the supernatural, it rarely overlaps with the actual crime genre.

I haven't seen the film myself, but after reading over the overview TMDb has, mystery seems like an okay fit to me. I'll leave this open in case anyone else thinks that mystery should be removed.

In english it's "mystery" in german we call it "crime". – In german we call "mystery" what in english is know as "supernatural".