I mainly book the hotel for its location, so can't be too picky over the quality. The room was not too small for central Paris, but the toilet is a retrofit and thus fits half of a person at a time.
The sheets and linens are not 100% white with the dirty mattress/pillow showing through. I had tingling on the skin touching the mattress side.
Heating was also less than ideal. The radiator was barely warm, which is probably why there's also an electric heater in the room. However, on a 2 degrees winter day, even with both on the room failed to reach 20 degrees and I ended up having to use the AC. Given cheap nuclear power in France, probably should just use the AC.
The worst problem is passing trains shaking the building. Sometimes some furniture would resonate as well, which makes the whole experience alarming. The trains stop around 1am but resumes at 6.
