The apartment is great. It is located just outside the Duomo (which you can see from the bedroom's window if you stretch your neck). It is located a walking distance from everything. The apartment contains a bedroom, living room, a kitchen and a bathroom. It is very clean.
Alessandro had waited for us on our arrival, even though it was very late at night (unexpected delay in the trains from Rome). He had shown and explained everything and was open to our needs.
I would recommend the apartment and the hosts (we have only met Alessandro though) to everyone.