Wanted to love this place-- the staff was warm and welcoming, however, they could not overcome the various inconveniences which made our stay intolerable: NO AIR CONDITIONING on floors 3 and above (!?@#$%), supposedly free "wireless" internet connection in each room did not work, and had to bring laptop down to the main floor parlor in order to use it, AND worst of all, the room was SO LOUD that even with earplugs we could not sleep at night. Of course, since there was no AC, it was necessary to keep the windows wide open, which made the noise level even more intolerable! It was so loud, that we had our TV on the loudest audio setting, and still couldn't hear it. (Our hearing is fine, by the way!)
Further, the configuration of the toilet being in a separate non-ventilated room than the shower/sink or bedroom, was not only stifling, but totally inappropriate for a room to be used by more than one person ; p
To make matters worse, when I tried to contact the hotel group designhotels.com, in days after, I received NO REPLY to my repeated e-mails, phone calls, and snail mails. I guess they don't care if they have repeat business.
Also, although there is a convenient tram line on the same street as the hotel, this is NOT in a convenient part of town, and requires a good 15-20 min. walk to get to anywhere you want to be...

Stayed for two nights. Each floor is themed and designed by local German artists. The first room was Green and based on "childhood" - facing the very busy street unfortunately it stank of cigarette smoke, despite being advertised as non-smoking.

No problem, the receptionist was very apologetic and moved me to another room, this time themes "dreams". This was a better room being located at the back of the hotel where it was more quiet and I would definitely recommend that given the choice the back is better as the fron has no view to speak of.

Near the hotel are various restaurants and cafes so if you don;t fancy eating at the hotel it's not a problem.

There is a tram stop outside - No 11 and it takes about 13 minutes to get to Wily Brandtz Plat which is quite central.

WIFI is free and the showers are powerful, toiletries are from Aveda.

One thing to be aware of is that if you are staying for pleasure, the housekeeping start to make up the rooms from 8:30am. Which is the earliest I have seen.

The owner has several bars and restaurants in the city and the hotel is certainly very stylish.

For the money,it is hard to fault especially in Frankfurt where €150 for an average double is the norm.