Corrected entry: Popeye's gun changes between a 6-shot Colt Detective Special and a 5-shot Smith and Wesson Model 36. Near the end of the movie when he thinks he's firing at Frog One, he shoots it eight times.
Corrected entry: The French hitman hijacks the subway train and orders the motorman not to stop at any station. But why? He has no idea that Popeye Doyle is doing something as quixotic as chasing the train by car.
Correction: This is not necessarily an error. The hitman may have anticipated that Popeye would radio ahead to the next station to have officers arrest him when he emerged from the train or may have thought that stopping at the next station would provide Popeye with time to catch up to him while the train was stopped at the station. If the hitman's intention is to put as much distance between himself and Popeye as possible, doing what is necessary so the train does not stop at stations is plausible.
Corrected entry: When Charnier is still in France, he takes a gift to his girlfriend. She goes inside, and he picks up a fishing pole. He turns, and she comes back outside. The pole is gone. There was no indication he put it down or dropped it over the wall.
Correction: The fishing pole is actually still there. If you look very close, to the very right its still resting on the rail. You may have to play it a few times, but it is most certainly there.
Corrected entry: When the police investigate the car in which they suspect drugs are being hidden, they really tear it apart - they rip out linings, pull apart fittings, pry off bits and pieces, etc. However, when, after a short period of time, it is returned to the actor who brought it in, he does not notice that it has been tampered with. It really would have taken a much longer time and a lot of the right fittings and materials to put it back together again in such good condition.
Correction: The car which is returned to the owner is a different car that is identical to the original.
Correction: This would only count as a mistake if the type of gun changed between shots...if that's what is meant, the specific time it happens should be made clear. Also, he reloads in the final scene, so firing eight total shots is not a mistake.