This is a tower widely used by the East German government along the border dividing east and west Germany from each other.
This is a small version displayed at a museum. The ones that where actual used are higher.
Wikipedia Article about the Inner German border mentioning this type of tower.
https://en.wikipedia.org/wiki/Inner_German_border
My 3D model from photos generated with photogrammetry software 3DF Zephyr v4.530 processing 18 images