Kar Wai Wong who also did the film I found awful, Happy Together, and the film I found average, Chungking Express. This one actually stars one of the main characters from Happy Together, Tony Leung Chiu Wai. Alongside Maggie Cheung, better known for her role in Hero with Jet Li.
The film starts with Tony's character looking for a room to rent, he answers an ad to find that Maggie's character just took the apartment. The owner renting the room sets him up with her neighbor and they end up moving in on the same day as new neighbors. They are both married and their spouses travel a lot for work. Then they both come to the conclusion that their spouses are having affairs they form a friendship consoling each other. They even act out scenes of their spouses breaking the news of the affair to each other.
Personally I couldn't really tell if they were having an affair themselves or were just being cautious about their friendship being misconstrued. The film was boring, and I especially don't like romance films centered around affairs, especially the painful side of them, and this film is full of pain and heartbreak which is not something I desire to watch. I wouldn't suggest this to anyone just looking for an interesting foreign movie to watch Infernal Affairs or Hero if you really want to see these two stars perform.
IMDB Link: http://www.imdb.com/title/tt0118694/