Sonora is the place to stay in Mexico city. Very close to La Roma, a nice area with lots of cafes and restaurants. Also very green: in front of Mexico park and Avenida Amsterdam. Very convenience to drive to the airport.
Katrin's apartment was an amazing option to stay. Very clean and well-organize. Confy beds, two full equipped toilets, quiet and safe to stay up to 6 people (3 king size beds/3 bedrooms). I can't say a negative thing but only thank Katrin for making things so easy for us and hosting at their apartment.