Shots of the reel to reel tape recorder, supposedly recording, had the device in 'play' mode , not record mode. In record mode the play/record selector turns a further 30 degrees.
The 'tapes' stacked on top of the filing cabinet are 9 track half inch reel to reel tapes , not quarter inch audio tapes.
The red Mercedes used throughout the series has a Munich number plate with 5 digits. Standard number plates are limited to 4 digits in Germany.
Several times in the series, Charlie calls Gadi "José" - the Spanish pronunciation (ho-zeh). This is an obvious mistake because Charlie and her actor friends give Gadi the name Joseph since he won't reveal his name to them. The correct pronunciation (and the one in the book) should be "joze" with the hard J and the silent E.