The venal man we come to know doesn't exist in movie-movie land, the way De Niro's Capone does, or Penn's Cohen does. Rather, he's human-scaled — a monster in many ways, yet a dimensional one. When Arestrup (best known to American audiences for his kindly French farmer in "War Horse") receives his comeuppance at the end of "A Prophet," it's a complicated moment for the audience. Arestrup does it all with a look: He's trying to get his former protege, the Algerian kid played by Tahar Rahim, to venture over to his side of the prison yard. But the kid has been mistreated too long, and he is now a kingpin himself. And the old man is left with a pleading look on his face that says: It's over.