Sorry it took so long. We don't have our own parking. The closest safe parking costs Eur 18.00/ 24 h. On the street it will be Eur 2,50/ h.
They do valet parking for ca. 20€/day or you can park on public lots that are located within a few hundred metres radius from the hotel. They have a tight back yard where they occasionally allow one car. (=something you cannot rely on).
You can self park a short walk away, but we elected to valet park for 18 euros.
Get an answer from Hotel Gutenbergs staff and past guests.