Right by the main train station (2 min. walk) and in the area where you find a lot of the best ethnic restaurants of Frankfurt. The red light district starts a few blocks further up from the water and won't be a problem unless you go looking for it. Lots of artists and freelance professionals/academic types stay here. Great old billiard room. High ceilings, large rooms. Once you let the shutters down the noise and streetlight are gone. The breakfast buffet is delicious, the room rates reasonable.

I literally scrawled through hundreds of hotels as i am quite picky. I eventually decided to go to hotel Nizza with my sister for the christmas markets, and i wasn't dissapionted.
The hotel was i think in the perfect location, don't belive the hype about the red light district, the hotel is just round the corner but i didn't even notice it was a red light district ....the most you notice are a few late night (shall we say adult bars) dotted around. We walked round the area together late at night and didn't feel worried at all!
The hotel is really nice. I'ts a mixture of antique furniture and modern lines, obviously designed by someone with great taste. The actual hotel was just a nice size and just round the corner from the train station but in a suprisingly quiet spot. We just walked over the road to the train station every day and travelled to anywhere in the city within a few minutes on the underground (so handy). The staff were fantastic, i mentioned on the way up to my room that we wanted an easygoing night out as we would be shopping early the next day. I asked the night porter/reception man if he new of anywhere with good music maybe jazz (not the overworked rubbish type) or maybe a band etc. We went up to our room and when we came back down he had gone on the computer, google earthed it and showed us how to get to a really good underground jazz bar. He was so helpful. We went and it was fantastic. It was called jazzkeller, there was a bassist, pianist and drummer playing christmas songs in a jazz style.
Breakfast was really nice, fresh and varied.The room was lovely although quite minimal. The only criticism i would have is that there were no drawers for clothes and toiletries etc so we had about four hangers each and the rest of my stuff was kept in my suitcase. Also they didn't have any beverage facilities in the room which was strange ( the higher priced rooms might have).
So if it wasnt for a couple of small things i would have given hotel Nizza a 5/5

We visited Hotel Nizza as a family, on our way to and from Lapland, taking in the Christmas Market. The hotel was chosen with price and proximity to the market in mind. We walked there each day, and found the personal attention we received from staff wonderful.

The hotel itself is old, but comfortable, clean and well run. We thoroughly enjoyed our time there.

The proximity to the red light district is only an issue if you head that way. As all our travels took us away from that area, it was not even an issue.

Hotel Nizza is a real gem of a hotel just three blocks from the main train station in Frankfurt. What a pleasant surprise after our 11 hour flight to find this pleasant, charming little hotel tucked away on a quiet street but within walking distance of the main train station. The rooms are large and bathrooms are nice. The rooftop garden is an added bonus. We toasted our safe arrival in Germany up there with a glass of wine and some snacks. The staff is friendly and helpful and the breakfast was beautifully presented with many choices of delicious cheeses, spreads, yogurts, various breads, and coffee drinks made to order. We stayed here both at the beginning and the end of our trip. We enjoyed playing pool in the large recreation room available to guests.