When Jules, Jim, and Albert are sitting on the grass sharing stories about the war, the order of the three characters repeatedly changes between shots. Note that this is actually a goof on the Criterion Region 1 disc, and the Tartan Region 2 DVD, in which the film is reversed left/right. It does not occur in other DVD releases of this film, including the Fox/Lorber Region 1 release.
When Jim has to return to Paris after his long stay, he jumps onto a train where the locomotive pulls two passenger cars and a cargo carriage (in that order) out of the station. After the cut to a longer aerial shot, it is pulling a cargo carriage and three passenger cars.
When Jim arrives by train at Jim and Catherine's house in Germany, a shot from the air depicts a French (SNCF) train. When the train arrives in the station in the next shot, the SNCF logo is hidden from sight.