In the day since seeing it, Un Prophète has matured in my mind from one of the finest movies I've seen (not least for the sustained, perspectival morality necessary to and motivating its formal amorality). As I say, it has matured in my mind over the last day from one of the best movies I've seen into one of the best interior experiences I've had. The pregnant bleakness of this movie reminds me of only one other cinematic creation I know: those stony, white-painted, hard-staring scenes from Fanny and Alexander set in the Bishop's house.
There are other correspondences between those Bishop's house scenes and the French prison scenes: the cinematic treatment of white, bright sunlight as a symbol for a certain kind of insistent evil - the peculiar evil latent in bleach or lime.