Cologne - Scales of justice

Apparently, for some works, the explanatory table should be nailed (placed) in a more prominent place. Best directly on the forehead (figuratively). Fortunately, we have the Internet, and there is something that can be googled today.
At first I thought that the somewhat mysterious-looking system of two hemispheres and an obelisk was somehow remotely related to the nearby war memorial. It's actually related to the building across the street (to the south). The…