The apartment itself is nice, has two bedrooms and two bathrooms and a fully-stocked kitchen. It has AC, so you won't die from the summer heat :) A laundry machine is available, too. The location is perfect for exploring Florence on foot - everything you need is in walking distance. The famous historic sites are just a few blocks away, as well.
It was a bit tricky to get to the place with our car (you need to drive into the ZTL where it says "only authorized vehicles") in the first place, but once we got there, our super friendly and helpful host welcomed us, showed us the apartment and helped us find the way to a very good parking garage nearby. Note that you will need to register your car's license plate within 3 hours of entering the ZTL or you might be hit with a beefy fine!