I have not slept at Paula's place : Paula proposed me to rent another flat by a friend of her in the same street, because it was easier for her due to our departure time. But everything was very easy, the second flat was very beautiful, cosy and clean. And the surroundings are wonderful : the little streets around are full of bars, restaurants, nice shops, the museums, the Retiro, Atocha station, St Anne square, plaza del Sol, etc. are only in a few minutes walk. A nice place to discover Madrid and a nice host I can recommend. Thanks !