When Dany turns sharply into the gas station to refuel the car loses a hubcap, yet when the car comes to a stop at the pump all four hubcaps are still on.
After Georges/Stephano dumps the body in the rail yard (at 1:11), you can see the body is between the rail and a yellow piece of equipment. After he hugs Dany, he goes back to the body and it is now on the rail and about six feet closer to the Thunderbird, not under the machinery.
In the subtitles, the GUN is identified as a SHOTGUN. However, the prop used in this movie (in all scenes where it's clearly visible) is a rifle, aka a gun. This is a subtitle translation error and not a movie goof. The characters in the movie refer to the gun (in French) as "le fusil" which simply translates to "gun" in English.
(at around 45 mins) Georges/Stefano says "I disconnected the battery", but you can clearly hear the battery powering the start motor.
The large back tattoo Elio Germano has is anachronistic for 1972 when the film is set.