I just saw it yesterday in one of the theaters around here. A Prophet got overwhelming positive reviews, in addition to the Grand Prix at Cannes 2009 and the BAFTA for best film Not in the English language.
Though the story of a young guy surviving prison was told a million times before, A Prophet is a well-told story, the main characters (a young French-Arab and an a middle-age French-Italian mobster) are given all time needed to grow and mature and that's the movie's strongest aspect. Unfortunately Audiard's pretentious use of Islamic religious references (mostly verses from Koran, ghostly appearances, and the movie title itself ) reveals his (as expected) ignorance in this aspect. He also claimed in an interview that he wanted to draw attention to Arabs in a different way, but he didn't: this movie is not about Arabs in France or Europe, it's about a specific Arab guy who -during his prison time- wasn't accepted by the two major mobs inside (an Islamic, and an Italian one) for very specific reasons. In addition all the scenes that had ghosts or visions of religious aspects didn't advance or add to the narrative anything (more of a distraction).
Overall it belongs to the same category of European movies ready-to-digest abroad, like The Lives of Others a few years back (though the latter was a better work).
Quick Review:
Trailer:
