We could not meet Oscar in person as he was out of town but he provided exact description how to reach the apartment and friend of his was waiting for us.

Apartment has everything you need to feel you are at home.

As you can see from the map it has central location, close to several Metro lines and Atocha train station. Half of the interesting points of Madrid are 10-15min walking. Close to it there is a big supermarket that works till really late.