The problem I have with Roger Ebert's review
http://rogerebert.suntimes.com/apps/pbcs.dll/article?AID=/20030627/REVIEWS/306270304/1023
You ought to read it. All of the things which he cites as negatives, I see as positives. I believe the dialogue is witty and the lead performances are superb. In fact, Jean Reno deserved an Oscar nomination. The thing is...it's realistic. Unlike the "Before Sunrise" characters, these people have lengthy pasts and many life experiences that have formed who they are. They are both cynical and world-weary and can only seem to relate to each other. IMO, there's a lot of depth in the movie. Ebert seems to think that it's simply a shallow retread of other movies.