Factual error: In the beginning when Stauffenberg is writing in his diary, his handwriting has a modern style. Born in 1907, Stauffenberg would have used either the kurrent or the sütterlin handwriting, the latter being introduced in schools from 1915 on. Both look very different from what we see in the diary. (00:02:16)
Factual error: Approximately three quarters of the way in to the film, there is a close up of a German soldier handing an officer a file of documents. The helmet that the soldier is wearing is a post war 1960s version. This can be determined by the lack of an air vent and rivet on the side of the helmet.
Factual error: In one of the scenes, a bathroom is shown. The tub has modern fixtures, including a hand held massage/rinse nozzle with flexible metal hose.
Other mistake: During the scene of the attempted coup at the SS ministry, several officers are wearing heavy winter coats and gloves. The action takes place on July 20th.
Factual error: Characters in the movie were drinking champagne from tall slender flutes; the style that came into use in the 1970s and are still used today. In the 1940s champagne was drunk from coupes or champagne saucers which are wide and shallow, much like margarita or daiquiri glasses.
Factual error: The tail insignia on the silver transport plane (the red with the swastika) was discontinued after 1935.