I was observing from the train yesterday, and there is a charger visible on the north side of the building, to the left of the green arch, where an ID Buzz and possibly an e-Golf were plugged in. The coordinates match with those on eCarUp, but I'll need to visit by car at some point and see whether it's really this one and whether they installed any QR code.
EDIT: it's the same charger also visible on Chargemap pictures, so it must be the one.