Solid four stars!

Pros: Great location next to the Pantheon, Sorbonne, and Luxembourg gardens. Marie was very responsive and pleasant, and the apartment was clean and lovely. There is a great sitting room with a mini kitchen, which was very useful for storing snacks/making breakfast, etc., and the view from the balcony is wonderful. Marie was also very helpful in letting us know the best way to get to the apartment via public transit, and had her housecleaner's husband stay a bit late to let us in at 4pm.

Things to improve/note: Wifi connectively was unstable, which would be difficult if you needed a reliable connection. Also, this is not an entire apartment - it is part of a bigger apartment, but has it's own door and lock. If you wanted complete privacy, that might be a concern. Finally, despite the hosts living next door and us staying for a week, they didn't stop by or say hello, which I thought was a bit odd - but they might have just been trying to give us our privacy. A guide for the apartment (check-out times, where to leave keys, etc.), building, and area would have been a big plus as well.