Du Rififi au Cine and the follow-up Du Rififi au Cine Vol. 2 are both must-have collections of French crime jazz which are jam-packed with great music, although I see they're now out of print and pricey.
Eric Demarsan's score for Melville's Le Cercle Rouge is still available though and, need I say, wonderful.
Philippe Sarde's score for Georges Lautner's dark 70s political thriller Mort d'un pourri is also available and a damn fine piece of work featuring Stan Getz at his noirish best. I can't recommend this one highly enough. Amazon France has clips available for this album - don't know why Amazon US doesn't.