William Friedkin's hard-hitting police thriller about a pair of narcotics detectives on the trail of a French drug smuggler set the standard for future cop movies, and is infused with the grim naturalism that came to define much of early 70s cinema, especially with its gritty New York locations. Gene Hackman and Roy Scheider are both excellent in their roles, and Fernando Rey, as the impeccably sophisticated and unflappable drug kingpin, is an inspired casting choice.
The highlight is the car chase filmed under the elevated subway tracks, a marvel of editing, cinematography and stunt work (supposedly filmed without the necessary location permits) that is rightfully one of the most celebrated chase sequences in film history.
The film is also filled with little details (both in the writing and execution) of the kind that today's filmmakers can't be bothered with, but which add up to so, so much in creating a vivid atmosphere. The ambiguous ending, which would never fly today, effectively avoids the trappings of the neat-and-tidy conclusion and is a key part of what makes this film so special.
Seen in a good 35mm print at Loew's Jersey.