As previously mentioned, The French Connection is inspired by the real-life "French Connection" heist, which involved detectives Eddie Egan and Sonny Grosso going at all lengths to end the smuggling of heroin from Turkey and France to the United States. The film itself is very dark and extremely intense throughout the majority of the picture (as were many films about rogue main characters in the 1970's), but this is also one of its greatest strengths. There's no reliance on vast quantities of special effects or nonstop action during every single minute. It's just two detectives embarking in a cat-and-mouse game that stays on the edge of your seat through realistic and captivating events, told masterfully by Friedkin's direction and the power of its lead actors.
Hackman and Scheider are forces to be reckoned with as Popeye and Cloudy, respectively. This film was Hackman's first in a leading role, and it proved he could really take on such a task. He really gets this character of Popeye, mustering up as much ruthlessness and strength as he can to portray this tough guy with all intensive purposes of adhering to the law. Hackman is entirely believable as Popeye as a result of this and does not take mercy for an answer unless as a last resort. What makes The French Connection work so well, though, is that Popeye's actions are constantly questioned and sometimes disagreeable throughout, especially when he thinks he has the right answer but somehow always one step behind of Charnier. The film garnered Hackman an Oscar for Best Actor as Popeye, and after watching his portrayal in the film, it's very easy to see why he won.
Scheider is great as well, albeit with a little more caution to his step than Hackman's character. He's the perfect foil as Cloudy and prevents Popeye from going completely over the edge most of the time, helping him stick to the boundaries of the law as necessary. He's also great as Popeye's best friend, celebrating with him when they make advances in their chase and so on. Scheider would go on to land a starring role in Steven Spielberg's first blockbuster success Jaws, further cementing his status as an established actor in Hollywood cinema.
There are a few aspects to The French Connection which may not necessarily work for some audiences today. The film's pace tends to lean more on the slower side for its first half, giving time for to establish Popeye, Cloudy, and Charnier for their ambitions and goals. The pace isn't uneven, however, as there are perfectly balanced moments of action and drama between the detectives' investigations and Charnier's plot coming together. The second half of the film creates the ultimate payoff with an intense foot chase through the subways of New York, and later an even better second chase by car and train as Popeye goes after one of Charnier's snipers. Without giving away too much detail here, the latter chase is one of the best to have ever been put on cinema, having the right amount of terror, adrenaline, energy, and intensity all wrapped up in one gritty package, filmed with little to no special effects at all. It was often reported that stunt drivers hired for The French Connection often miscalculated the timing of certain actions throughout the chase, leading to collisions which remained in the final product while the stunt drivers were ultimately unharmed.
If there's one other important element of The French Connection that's both startling and in perfect synchronicity, it has to be the highly experimental jazz soundtrack created by avant-garde musician and composer Don Ellis. Ellis was best known for having unusual ensembles of instruments brought together in his orchestras, including multiple double basses, different kinds of trumpets, and an amplified string quartet. He pulls no stops here and even uses his other experimentation to great effect - the exploration of microtones and quarter-tones (or, pitches in between the "black and white piano keys"). The main title sequence for The French Connection introduces all of these elements in jarring and glorifying fashion, sounding incredibly dissonant and uncomfortable in establishing the heavy atmosphere the audience is about to be introduced to. This dissonance especially comes from the blaring use of six trumpets at the beginning (three play normally while three others are in quarter-tones, with Ellis at times also performing in the score on his customized, personal, and specially-made microtonal trumpet). Without giving away the ending of the film, the score does a great job as well in tying together the whole experience using these same unnerving elements together.
The French Connection, from the very first second of opening credits, is uneasy and right on the edge in taking risks. From the gritty cinematography to the drama unfolded on screen and its terrifying soundtrack, the film is a masterful work of art and an excellent showcase for its two lead stars and Friedkin's own direction. Uncompromising and brutal, yet realistic and energetic, The French Connection is a great thriller and an even better work of enigmatic, intensifying drama.