The Tenant is a very strange film taken from a very strange book. The book kind of determines it, but not entirely. I read the novel (novalla really) for this book club I'm part of. After we talked about the book, then we saw the movie. There was some debate over whether Roman Polanski is the only European in the movie. He's not. Most of the cast is French. Their lines are dubbed into very American-sounding English. Except that Melvyn Douglas and Shelley Winters are in it, and they speak US-English despite their characters being French. So it looks like Polanski himself was jumping between languages depending on who else was in the scene.
Then there's the main character going nuts. That part's very vivid.