The apartment was clean and as the photos have shown. The check-in experience was great.
Unfortunately, the wifi did not work and the issue was not resolved during our stay. As it is an old building and the walls are very thin you could hear the neighbors next door and also other guests when they were using the stairs. I‘d say the apartment is not suitable when traveling with small kids because of the many stairs (there is no lift) and also because of the balcony access in the apartment itself which could be dangerous.
However, the location is good if you would like to visit the Retiro Park or the museums there. It is also very close to the city center.