For those of you looking for a TLDR:
It's a very nice little flat in a quiet part of Paris, but still close enough to the city centre.
For those looking for a little more in-depth review:
The flat is very cosy and fits two people very comfortably, with ample room to sit and lounge. The terrace has a nice view and gets lots of sunshine. Everything was clean and pretty much as advertised. The kitchen is fully equipped with a microwave and oven, should you decide to eat in and there's even a tiny little dishwasher to clean up the plates.
There is still a bit of construction going on outside, so if you're not staying over the weekend like we did, you'll have some pretty noisy drilling going on in the morning. Thankfully we only heard a bit of it on Monday before checking out.
All in all we enjoyed our time at Marie's flat and would recommend it to friends.