Carlotta's apartment is situated in the heart of old-town Bologna. It is six or so stories up, on the very top of a quaint residential building. The building has no elevators - which is something to consider if you're not in a shape to take six flights of stairs.
The apartment itself is small-scale (functional living room, kitchen, two-person bedroom), but very comfortable if you're alone or with two people. It has great views on the city and its surrounding hills on either sides.
The only negative was the low water-pressure in the shower (it does give hot water, but don't expect a waterfall), but that was definitely manageable and didn't at all diminish our stay.
Carlotta was a great, communicative host, who made sure our stay was perfect.
Highly recommended!