Corrected entry: Early in the film, where the two main characters are on the train from Paris to Venice, overhead exterior shots show the train on the LEFT hand track, whereas in continental Europe it would be on the RIGHT (like driving on roads) so the train is probably British stock footage.
Correction: In France, trains drive on the left: http://www.sinfin.net/railways/world/france.html.
Correction: Trains occasionally run on the left-hand track - if the other track is undergoing repairs, for instance.
Twotall