The apartment was beautiful and just as described. Delphine's communication was fast and friendly. She gave us a great recommendation for a local bistro (Dynamo) which is very close to the apartment.
Do be aware that the apartment is at the top of a steep hill that is accessible by one road or via staircases. If this isn't a problem for you, then you are rewarded with a really quiet neighbourhood, with a beautiful view of the Sacré Cœur from the end of the street. It's magical at sunset. You can also see the Eiffel Tower if you stick your head out of the living room window and look right.
There are four metro stations within easy walking distance of the apartment, as well as the beautiful Buttes Chaumont Park. I would heartily recommend a stay at Delphine's place.