Sergio's place is perfect and we felt very much at home during our stay. Sergio was very helpful and met us after we got lost trying to find the apartment when we got off the bus. It is in a great location close to the historic centre and all of the major sites and also only a few minutes from both train stations and the metro. The area is perfectly safe as long as you stay on the main streets to the centre of the city. Would highly recommend staying in Sergio's apartment.