The Hotel Zentrum is undergoing / nearing completion of renovations - although they did not bother us in any way.
The hotel is situated in an excellent location - literally 50 m from one (of the several) exits from Hauptwache S station. Note: if coming from airport, take S8 or S9 and 2 stops past the Hauptbahnhof will find you at you destination. A simple and easy way in/out of Frankfurt. If taking rail, the Frankfurt Hbf is about a 15 minute leisurely walk up Kaiserstrasse from hotel.
The room we had was clean, bed very comfortable and bathroom nicely renovated.
A great bonus was the inclusion of a self-serve breakfast within the room rate (not always the case). Late day / evening coffee and cake in breakfast lounge was also a pleasant treat.
The location to the heart of Frankfurt was excellent. Walking to Freegasse or Kleinhalle market or even across the river to cider taverns was all feasible. Shopping (Zeil area) is within 2 minutes walk.
Good choice for Frankfurt stay. More