I lived here for six weeks while attending culinary school in Paris. Overall it was an amazing stay - incredible location, plenty of space. It really came to feel like home.
A few details:
Location - one of the best places in Paris to stay. It's in the more genuine, less-touristy part of the St. Germain neighborhood - with wonderful local restaurants and bars literally next door. It's within easy walking distance to the Seine, Notre Dame, the Louvre, Luxembourg garden, and so many other Paris highlights. Also very easy access to multiple metro stations - there were very few places in the city that weren't a straight metro shot away. Cannot go wrong with the spot.
Unit - bright, airy, charming; I totally fell in love with the space. It has a large living area and separate large bedroom/bathroom combo, which was very different from many of the other units I found in Paris (which tended to be true one-room studios). The couch folded out into a large bed, so this could easily sleep a family of 4. The kitchen was European-small but did the trick, and the unit included some niceties like a dishwasher and washing machine.
A couple things to note:
Noise - the downside to being so close to popular bars and restaurants is that there are lots of people around the neighborhood at all times. The streets right around the apartment are some of the most popular nightlife areas in the city. That said, Anne has done an amazing job sound-proofing this apartment - all the windows are modern double-paned and perfectly sealed, and there's an additional metal shutter for the bedroom window. Despite some incredibly loud nights, when I closed and sealed all the windows the apartment became generally perfectly quiet. There was only one night where I needed earplugs to sleep - after France won the World Cup. I doubt there was anywhere quiet in the city that night though.
Heat - Air conditioning isn't really a thing in many apartments in Paris, and this unit being on the top floor could get somewhat hot. I was there during some of the hottest months of the year, and it certainly got warm, though not out of the ordinary. There are a number of fans around the apartment (including some I added to the collection) which cool the place down fairly well.
Stairs - it's on the European 5th floor, so lots of stairs to get up and down. This didn't end up bothering me much at all - the charm of the loft-like top-floor unit was totally worth it.