At several points in the movie, Günther speaks in French to German officers.
The coat of arms from the Romanian flag in front of the hotel where the French delegation has been accommodated was adopted only after 1965.
When Jo and Gunther leave the hotel there is a sign for the German Automobile club "ADAC" hanging on the wall, using the design of the 1950s. Furthermore: While the ADAC was found in 1903, when the Nazis gained power in 1933 all Automobile clubs in Germany were combined as "Der Deutsche Automobil-Club" DDAC, whose logo also didn't resemble the ADAC logo.