Continuity mistake: During the car chase scene under the "B" Elevated Train in Brooklyn (86th St.), Popeye passes the same curve at least 3 or 4 times. Look closely, you'll probably see the same movie theatre over and over again. Apparently, they rerun the same chase clip to increase the length of this scene.
Trivia: The casting of Fernando Rey was an accident. William Friedkin had wanted to cast Francisco Rabal, whom he had seen in Belle de jour (1967), but at the time didn't know his name. Only after actor and director met did Friedkin realize Rey wasn't the actor he had wanted. Friedkin ended up keeping Rey after learning that Rabal spoke neither English nor French.Cubs Fan
Trivia: During the subway chase scene Hackman collides with another vehicle. This wasn't supposed to happen and the vehicle wasn't even supposed to be on the set. The crash looked cool, so it was kept.
Question: Why does Sal take the dirty car out of the city parking lot and park it by the docks? If that's the drug car why would the French let him do that?