The nuclear power plant is apparently located in landlocked, open countryside. There does not even seem to be a small stream or brook nearby. That is not possible. Commercial nuclear power plants have water-cooled reactors and need to sit on a riverbank or on the sea shore for a reliable supply of ample cooling water.
The police car used by Egon in 1953 is actually a model from a much later year as evidenced by the large rear window. A 1953 beetle had a small oval window in the back.
When characters use telephones throughout the series, the typical American "warbling" ringing tone is heard instead of the German "beeping" ring. Also, when speed-dialing is used, the touch-tones are heard in rapid sequence as in America; phones in Germany don't do this.