Melville seems to be having a joke with this, his last film. The laughably inept model train & helicopter work & the obvious studio "street" in one brief shot seem deliberate, as if Melvile is seeing what he can get away with. There is more humour in the scene where Crenna & co, dressed as medical staff look like bizarre ghost-gangsters accompanying Deneuve as an angel of death-like nurse...very mock Cocteau.
The obligatory & protracted heists we have seen before. In "Le Cercle Rouge", Melville gave us an alcoholic redeemed...in "Un Flic", there is no such hope. Cops, criminals & victims are one & the same...figures of sadness against a cold, blue backdrop and accompanied by Michel Colombier's stirring, yet resolutely downbeat theme "Thalassa" (from his album "Wings", a record that Melville admired).
This film is no "Cercle Rouge", it is a bizarre & dreamlike drift through traces of Melville, there is no romantic death to close this film, rather Melville ends the film (and his career) with banal melancholy, fittingly, the "futility of effort" that lies at the core of much of his later work has the last word.