The former west-east border near Lübeck in the 50ies
That sign has been located some steps before a wooden bridge over a small river near Lübeck with the border in it’s middle; the bridge part over the east german part has been broken of by the east german troops. The sign meant: "Stop! Here zonal border! Federal Border Police". The Federal Border Police now has the name "Bundespolizei": "Federal Police". "Zonengrenze = Zonal border" is a notion from that times as there has been 4 occupation zones in Germany after WW II: The american, the british, the french and the soviet zone. After the other ones have been ended, the soviet zone doesn’t end but has changed in an communist separate state named "Deutsche Demokratische Republik/DDR", misusing the word "democracy" (German Democratic Republik/GDR).