Francesco was extremely helpful and responsive by SMS and emails before my arrival. He picked me up at the bus station to walk me back to his flat.
The flat: quiet, with everything you need: kitchen, bathroom (with towels), spacious bedroom (that you can lock with a key) with a comfortable bed, a desk, a small table, a chair, a mirror and a wardrobe.
Everything was clean and tidy (bedroom, bathroom and kitchen).
Additionally, there is a very pleasant small patio to have breakfast or just to relax after a long day walking in Venice.
Of course, there is WiFi in the entire flat.
The flat is close to the piazza Roma (5 mins walk), which means it is not so close to the piazza San Marco (25 mins walking minimum, else there are vaporettos at Piazza Roma). The area is quiet and safe.
Overall I had a very good time staying in Francesco's flat and I appreciated his availability before and all along my stay when I needed him.
Just be aware his flat is not located at the exact point AirBnB shows it on the map. It is very close though (5 mins walk).