Looking for a movie

Hey everyone o/

After years of remembering to search for it and forgetting I finally felt like finding it.
I've seen.it about 10 years ago on german Arte and unfortunately I remember close to nothing but enough that I want to see it again.

It was a black white movie but made in the 90 probably. Not an old film.
The main character was a male and the story was around him entering a parallel world which is familiar to him but no one recognizes him.

Not even his girl friend or wife. I think there was a romance part with an.other girl later.
I don't remember how he entered it but it was just a door or some piece of furniture.

Later on in the movie I think there was a metro shot scene where he followed some some person or ghost.

I'm really sorry I can't provide more or precise information, these are stoned teenie memories, but I would be extremely grateful if someone happens to know what I'm talking about.