Rathaus has of course nothing to do with rats, unless you mean politicians. Which would be insulting to rats, I guess. Rathaus is from german words for a counsel (Rat) and a house (Haus) and means town hall.
The building is nothing extraordinary in the context of the town, but to the right side of it is a beautiful gate to the castle. Unfortunately you can only imagine the gate, because it was being repaired at the time of our visit so I could not take good pictures of it . And I did not have time to spend with the various plaques around the staircase either.