Visited yesterday without charging.
The chargers are directly accessible from the screen. 2 spots are painted with the regular eniwa scheme. There's a sign "Privatparkplatz Gashof zum schützen". The sign is only in front of one of the spaces but I assume the same conditions apply for both. While on location I couldn't figure out how that translates, but actually "Gashof zum schützen" seems to be the name of the hotel, so there's no additional information. I guess we need to ask permission to park there and use the charger.
One of the spots was ICEd.