Visited on October 24 and charged with Shell Recharge RFID.
The charger can be accessed without any gate, parking seems to be free.
There are some very discreet "Parkplatz nur für Gäste" signs further away. Given the very prominent paint and ban sign for the charger, it seems like it takes precedence over the Gäste indications.
There's a CCV contactless reader on the charger but it doesn't work.