Mathilde was one of the most responsive hosts that I have ever seen - you sent a message and in 5 minutes she is back :) her flat in Madrid is extremely lovely. The rooms are great and a bottle of cava was waiting for us in the fridge when we arrived. The flat is very central - 5 minutes to Lavapies and Empajadores metro stations. Also, the flea market on Sundays is 2 minutes distance to the flat :) I would definitely suggest Mathilde's nice flat for Madrid visitors.