I'd give it a B+, a pretty good grade for a movie I knew almost nothing about before attending. I selected it based on a few short reviews I read online, plus it seemed to be the best thing playing at the theatre close by, which is now my cinema of choice since I can walk to it and don't have to deal with parking.
I rather like foreign films. I generally don't know any of the actors in them, so nothing distracts from the plot. The story is the star. Too often in Hollywood/American films, I find myself distracted by the aura of a 'star' who has practically become an industry all to him/herself. An example of this is George Clooney. While I rather like looking at George, and I find him to be a decent enough actor, his celebrity image is so strong, it distracts from whatever film he is in. It's a George Clooney movie, rather than a film about 'X' which happens to star George Clooney. He's too famous to melt into any character at this point. Same goes for Brad Pitt -- he's too big of a movie star to be effective. He's a distraction, and if I were a director/screenwriter/whatever, I don't think I'd want him in my movies. But maybe that's just me.
Back to the film at hand..... I found "Roman de Gare" to be a bit of a whodunit, cat-and-mouse film, ripe with trickery. It's presented time sequence will have you question all that went before. It's clever, but not astoundingly so....just enough to be amusing. I'd give it 3.5 out of 5 stars in my foreign film galaxy. The ending clears up the loose ends pretty well, and while you won't spend a lot of time thinking about it post-movie, it's a decent piece of evening entertainment with some excellent performances. Definitely worth the walk down the street.