Let me start of by saying I absolutely adore Florence! Francesca's place is super cute and has the best possible location. You are situated a short walk from the train station (which is perfect if Florence isn't your only stop in Italy) and a few steps away from the duomo. You can not get any better than this and truly the place is perfect and my girlfriend and I absolutely loved it. There is also a supermarket right across the street! Next time I'm in Florence I will definitely stay here.
Note: it has been mentioned before but the restroom is downstairs and for us it wasn't a problem at all but I can imagine for some it might be.