When Dr. Bernhardt is being shown smoking a cigarette in the reflection of a passing train, the image is the opposite of how it should appear in a reflection.
In the opening sequence a group of young boys are playing at the Eiffel Tower when they pick up a dead pigeon. (a gunshot was heard but this is not explained) The boys take the pigeon home (presumably walking) which is near Sacre-Coeur in the Montemartre neighborhood. This is a distance of 5.5 kilometers or 3.4 miles. It's highly unlikely that 10 year old boys would play so far from home.
Around the time of the incident in Sulzbach, that is supposed to take place when the train is in Germany, the train is running on the left side. It shows that the shooting was done in France, where trains run on the left side, but not in Germany, where they run on the right side.
The narration for the final scene says the train arrived at Wannsee, in the far west of Berlin, but the scene shows them driving from the east, down Unter Den Linden and into West Berlin. The British and American then ask passing jeeps for lifts to their respective bases which they would have driven past on the way from Wannsee, whilst the Russian turns around and drives back under the Brandenburg Gate into East Berlin.