Un Flic is a French gangster caper film with many intriguing qualities. Visually, it is really interesting. The color choices demand repeated viewing. I like how there are seldom light colors seen (except for Deneuve's platinum hair and the smuggled cocaine). The muted color scheme generates a lot of gritty atmosphere to help draw you into Melville's nightmarish vision.
The plot is difficult to follow. I'm not really sure about several key points. For example, police officer (chief?) Coleman (Alain Delon) learns the name of the gangster the others had killed in a hospital. From that piece of information, they quickly trap the driver/helicopter pilot at a restaurant? Also, with the physically imposing driver/pilot in police custody, how does Coleman manage to break his spirit sufficiently to nab the rest of the gang? Torture would be needed, but no information is supplied to confirm it was used.
Much has been said about the obviously fake model train and helicopter that Melville shows for the second heist scene. I'm fine with it. (Gosh only knows how much it would cost to lease a train, a helicopter and pilots for a day.) The relationship between Delon's Coleman and Richard Crenna's Simon is a major theme. Coleman is a world-weary and cynical policeman who will employ brutal methods to solve crimes. Simon is an energetic and brave gangster/bank robber. Coleman is more romantically interesting to Catherine Deneuve's Cathy. However, Simon's courage during heist #2 probably wins the audience over. At the film's end we tend to like Simon more than Coleman.
Deneuve's Cathy is one of the richest small roles in screen memory. She's not on the screen for many minutes, but when she is, Cathy is a devastatingly enthralling femme fatale.
For a gritty, Hellish view of police and crime life; with three strong performances; along with a few toy trains and a helicopter, 'Un Flic' is One Crime Flick worth seeing.