This apartment was great, it was the first time we have stayed in an airbnb and the only thing negative I can think of is that it made us keep comparing the other apartments we stayed in afterward and wishing they were the same as Cozy Studio @ Paris Fbg Montmartre.
We didn't get to meet Estelle or Erwan as they were out of town but they had Serghei meet us and show us the apartment with instructions on how everything worked. Estelle was very prompt with communication before and during the stay, she also provided some very helpful information for the local area with her Guidebook.
The apartment is tiny but since everything has been thought out it works well making it feel cozy and not cramped. We felt very welcomed with the gifts of some treats and a small bottle of wine to settle in to the space. Everything that we would have needed was also provided (soap, shampoo, detergent for the washing machine, etc...).
The location is also great, it is in a quite courtyard with a lot of stores within a few steps. As stated in the description the Grands Boulevards metro station is a very short walk making it easy to get around the city.
I will definitely stay in this apartment again if we return to Paris and it's available.