Even though we didn't get to meet Cristina, the communication with her was perfect and we didn't get any problems to enter the flat.
As we had some flight issue, we arrived very late at night and she was even nice enough to leave some pasta and sauce for us to eat. So thank you again Cristina.
Still, the flat had many defaults so I would not recommend it to other travellers.
1 : several comments had mentioned the fact that there was a lot noise. It is more than that: the noise in the flat is constant. The flat is on the ground floor so you hear EVERYTHING that come from the street : the cars, the people,... As the street in front of the building is very busy, you have noise constantly : early in the morning, late at night ,...Even with the hearplugs, it's very difficult to fall asleep and the noise wakes you up early in the morning .
2 : there are no curtains on the window so as soon as the sun rises, it is difficult to sleep.
3: we had to vacuum the place EVERY DAY because there is dirt coming from the street : there is a small gap between the entry door and the floor so all the dirt from outside easily comes inside.
4: the shower is extremely small. So it is very difficult to wash your body. The shower curtain always sticks to your body which is not a nice feeling when you shower and is not very hygienic either.