"Rene is a 'ripou' rotten cop who makes ends meet by accepting bribes, presents and free drinks from the people he should be putting in jail. When his partner retires, he must team up with Francois, a young police school graduate with a righteous attitude. He is hard to break and Rene has to trick him. He introduces Francois to a charming girl and forgets to mention she's a prostitute. Now Rene has something against Francois he can use in case his partner should want to reveal Rene's little commerce with the underworld. The partners ultimately become friends, get one another out of a tough situation, and manage to gather enough money to buy Rene his lifelong dream: a small café near the horse tracks."
Philippe Noiret stars, and he's more than capable of carrying a movie. Born in 1930, he passed in 2006. Noiret was an impressive actor who never failed to make his part highly satisfying. His presence in a movie is a strong signal of quality. My first notice of him would be in Hitchcock's "Topaz" (1969), in which he plays a diplomat who commits suicide, I think. But he starred in the 1955 "La Pointe Courte" which has been discussed here not too long ago. He's in the 1962 "Therese" that's in Don's FF 6 package. He's well-known for the 1981 noir "Coup de Torchon". The 1975 one "The Old Gun" is another real winner.
The other actors in "Les ripoux" are perfect in their roles too. His new partner is played by Thierry Lhermitte,a prolific actor who is very capable of submerging himself in a role. He has a sub-plot romance here with pert Grâce de Capitani.
Why is this film a neo-noir? Well, I really don't know what defines neo-noir, but it seems in a good many cases to encompass a rather large comic component for one large segment of films. In such stories there is a conscious thing, a knowing and sometimes cynical thing, usually ironic in which very serious plots elements are disposed of with humor. It's almost reverting to the comic/detective/police story of the 1930s, but done with more depth.
In "Les ripoux", Noiret introduces the naive recruit to the real crime world of Paris, in which he's on the take, but with rationalizations and justifications, because that degree of corruption is what actually makes the system run and work. He has to overlook the numerous petty and victimless "crimes" that are made illegal by the legislators, like the gambling and prostitution, but even extending to the pickpockets for which there is no room in overcrowded jails. Resources have to be prioritized to get the bigger criminals, which in this case is some sort of drug dealer. That aspect is not treated all that seriously either.
Lhermitte's idealism and clean-living give way to a transformation under Noiret's guidance and plotting. This is the core of the movie and it's handled very cleverly. We buy into it. There is room for a couple of chases. This is not a dark noir in any real way, and it's virtually impossible to connect it to classic noir, even with the label "neo-noir". Maybe by stretching the perils and the term "alienation" and maybe by its acceptance of corruption as perfectly normal and making a hero out of the corrupt cop, this is what makes the connection between noir and neo-noir in this case.