Laura (Federico's friend) received us in the most charming way, gave us some great addresses and explain everything perfectly.
The location of the apartment couldn't be better. Supermarkets, pubs, wine bars, restaurants... everything you may need really close.
Walking distance: 20min to Vatican city. 10min to Campo di fiori and piazza Navona. 15min to the Pantheon. 30min to Trevi Fountain and the mouth of truth. and 45min to the Coliseum.
First floor by stairs.
The wifi didn't work very well and if you are a big person notice that the shower is quite small.

I recommend 100%