Good well decorated rooms with generous bathrooms. Rooms very clean. Breakfast is not lavish but of good quality. About 1km from the main train station, which was great as we had to go for an exhibition in Dusseldorf, and it was very convenient. The main shopping street Hohestrasse is just on the other side of the Dom / Train station and so also had lots of choices for restaurants and bars.
Price of 140 euros/night was reasonable for the exhibition period.
The rooms do not have free internet, so be prepared to pay 5 euors/24 hrs for this service. Parking is available.

Nicely located hotel which was ok, however not good value at €140/ngt. If you do stay here try and avoid the ground level rooms, and make sure you request non smoking as quite strong 'odour' in those that are (I arrived too late to change)

I stayed at this hotel for one night in July of this year and liked it very much. It's in a great location and when I say that I don't mean it's on the same block as the cathedral or the train station but it's just a several minute walk to either. I found the immediate vicinity of the Dom and the train station a little sleazy for my taste and things improved with every block further away from that area so the Hotel Harmonie was just the right distance as it was not a long walk to the Dom and not be in a sleazy area. I'd read in a couple reviews of this hotel that said the single rooms were a little small (I was traveling alone) and I didn't see any of them so I can't judge but for a few more euros I booked a double room and it was great. I would not hesitate to stay there again. Word of caution if you are driving a car: the driving in Cologne, especially in this area, is terrible. Even the locals will tell you that. There are so many one way roads and roads closed for construction I nearly pulled my hair out trying to navigate just a small distance in this town. Otherwise I had a good stay.

My oldest daughter and I recently stayed here on a World Cup trip that stopped in Cologne. The hotel is location very close to the main train station, and the Cologne Cathedral - which seemed to be the epicenter of activity for the city. The hotel was next to a church, so the ringing bells were a wake up call every morning - as we had to keep the windows open due to the unseasonal heat during our visit. The staff was very helpful and friendly. The room size was typical for Europe. It was very clean and the bathroom shower was large. The breakfast was included in the room, and was adequate. The only downside to the hotel was the limited wireless internet access. It was not free (nor was it free at any of the German hotels we stayed at during our trip) and the wireless signal was useless in our corner room. We had to go the lobby for it to work (which was just another reason to get a kölsch from the bar!). I would stay here again.