Hi Ignacio, we really enjoyed our stay in your Opera flat - the location was perfectly situated in the heart of Madrid to do all our tours by feet. Everything was in a walking distance. The cosy flat was big enough for two people, very quiet (incredibly quiet, like living in a little village), and the equipment in the kitchen and the bath room was modern, stylish and clean.
This was one of our nicest stays so far with Airbnb - a clear recommendation for everyone travelling to Madrid for a few days.
Greetings from Germany