Centric little flat close to the main metro/train station in Madrid. Walking distance to most touristic places. The area is very safe to walk at night, and not noisy.
The appartment is a bit tight but has all the needed ammenities, small kitchet, bathroom, main room and a second bed in the high room (which is open to the kitchen/living space). The appartment has a slight smell of humidity but nothing that would bother someone (unless you're too fuzzy about it).
Generally it's a good stay, particularly as the location is excellent.