<P> The casting of Fernando Rey as the main French heroin smuggler, Alain Charnier (irreverently referred to throughout the film as "Frog One"), resulted from mistaken identity . Friedkin had seen Luis Buñuel's 1967 French film Belle de Jour and had been impressed by the performance of Francisco Rabal, who had a small role in the film . However, Friedkin did not know his name, and remembered only that he was a Spanish actor . He asked his casting director to find the actor, and the casting director instead contacted Rey, a Spanish actor who had appeared in several other films directed by Buñuel . After Rabal was finally reached, they discovered he spoke neither French nor English, and Rey was kept in the film . Ironically, after screening the film's final cut, Rey's French was deemed unacceptable by the filmmakers . They decided to dub his French while preserving his English dialogue . </P> <P> The plot centers on drug smuggling in the 1960s and early' 70s, when most of the heroin illegally imported into the East Coast came to the United States through France (see French Connection). In addition to the two main protagonists, several of the fictional characters depicted in the film also have real - life counterparts . The Alain Charnier character is based upon Jean Jehan who was arrested later in Paris for drug trafficking, though he was not extradited since France does not extradite its citizens . Sal Boca is based on Pasquale "Patsy" Fuca, and his brother Anthony . Angie Boca is based on Patsy's wife Barbara, who later wrote a book with Robin Moore detailing her life with Patsy . The Fucas and their uncle were part of a heroin dealing crew that worked with some of the New York City crime families . Henri Devereaux, who takes the fall for importing the Lincoln to New York City, is based on Jacques Angelvin, a television actor arrested and sentenced to three to six years in a federal penitentiary for his role, serving about four before returning to France and turning to real estate . The Joel Weinstock character is, according to the director's commentary, a composite of several similar drug dealers . </P> <P> The film is often cited as containing one of the greatest car chase sequences in movie history . The chase involves Popeye commandeering a civilian's car (a 1971 Pontiac LeMans) and then frantically chasing an elevated train, on which a hitman is trying to escape . The scene was filmed in Bensonhurst, Brooklyn roughly running under the BMT West End Line (currently the D train, then the B train) which runs on an elevated track above Stillwell Avenue, 86th Street and New Utrecht Avenue in Brooklyn, with the chase ending just north of the 62nd Street station . At that point, the train hits a train stop, but is going too fast to stop in time and collides with the train ahead of it, which has just left the station . </P> <P> The most famous shot of the chase is made from a front bumper mount and shows a low - angle point of view shot of the streets racing by . Director of photography Owen Roizman, wrote in American Cinematographer magazine in 1972 that the camera was undercranked to 18 frames per second to enhance the sense of speed . Roizman's contention is borne out when you see a car at a red light whose muffler is pumping smoke at an accelerated rate . Other shots involved stunt drivers who were supposed to barely miss hitting the speeding car, but due to errors in timing, accidental collisions occurred and were left in the final film . Friedkin said that he used Santana's cover of Fleetwood Mac's song "Black Magic Woman" during editing to help shape the chase sequence; though the song does not appear in the film, "it (the chase scene) did have a sort of pre-ordained rhythm to it that came from the music ." </P>

Where was the french connection car chase filmed