The apartment is basic but fully functional. It has a kitchen and two bed sofas is good shape, so technically it can host 4-5 people, a bit tight though. The kitchen had everything needed.
Communication was smooth and the checkin was simple and clear.
The apartment was a bit cold, even with air conditioning on, since old buildings in Madrid have poor isolation, despite the good efforts of the owners replacing the windows.
The second issue with the isolation is that noise is rather intense: there is a construction site in front that produces some decent noise during the day and there is a bar right under the bedroom window that made sleeping a challenge until ca 2 am. Light sleepers might want to keep it in mind.