Great and cozy place. Even though I did not personally meet Justine, she is a lovely and very helpful host. Anytime I had a problem, it would get solved right away.
The flat is simple and clean and has got all of the essentials and more. It can get a bit noisy at night but that is to be expected in Paris and it did not bother me that much. My only complaint would be that the bed was a bit uncomfortable, as it was a sofa-bed instead of a regular one. Other than that, I had a great stay and would definitely recommend it.