After the Baron asks Flaemmchen for a date, he moves from behind her left shoulder to behind her right shoulder twice. Also, the Baron's cigarette seems to disappear without any indication he put it out.
When the Baron is stealing Grusinskaya's pearls from her trunk, they can clearly be seen as a very long strand of large pearls. But later when he pulls them out of his pocket to hand back to her, the pearls are small and on a shorter strand.
When Grusinskaya returns from her second performance, she and her entourage board the left elevator, and the porters carrying her flowers board the right. When they come off the elevator, the porters and flowers are on the same elevator as Grusinskaya.
Although correctly signed with licence plates starting with an "I" for Berlin, all the cars are right-steered. In Germany they drive on the right (and ever did so), so the wheels should be on the left.