The 'inside' joke here is that Yves Montand wears throughout the same jacket the Clint Eastwood wore as 'Dirty Harry'. This could have backfired badly had this movie laid an egg but as it turned out it is one of both the director and his leading actor's best efforts. No one writes in a vacuum, of course, and those with long memories will recall Charles Laughton asking Ray Milland to investigate a murder that he (Laughton) himself had committed and then making Milland the patsy. This in turn was echoed in Orson Welles' "Mr. Arkadin". No matter, we can always use one more outstanding thriller and this one fits the bill to a tee shirt or, if you will, jacket. Montand scores heavily, as you would expect, as the cop who is unaware that his boss is sleeping with his (Montand's) girl friend. When, one night, a quarrel ends in tears the boss, also unaware that he shares a lover with his best detective, assigns Montand to the case, and the fascination lies in seeing Montand peeling the onion that will lead to himself (he had gone to call on his girl friend, unaware that she had been killed and left, natch, clues to his visit). Montand's real-life wife, the great Simone Signoret, turns in a fine cameo as the wife of the police chief and the poignant scene where she asks Montand's help in shooting herself is not only a highlight but to those aware of the on-set drama surrounding the scene (Signoret had enormous difficulty in going thru with it)a fitting remembrance of one of the all-time great French actresses. A feast for Montand fans.