Fabulous. Everything was just as the other reviews say - so much better in person! I will add that not only can you see Notre Dame and hear its wonderful bells, but there are literally four other churches you can see from the balcony, and so you get various bells throughout the day. And at night, fun (but not too loud) music and energy from the street below. Plus, I ate a ton in France, and came back a pound lighter, thanks to all of the steps! Like your own private gym, that stairwell is!
Also, both Malin and Aurelien were very helpful, with directions and assistance. Aurelien was great at emailing and making sure we had everything we needed to get to the apartment, and Malin greeted us, showed us around, and even helped with getting us a great seat at dinner! (Thanks, Malin!).