Mary Laure was very accommodating, flexible, and helpful throughout my stay. The apartment was lovely and very comfortable. It really has anything you need for a short or long stay, and has recently been renovated. It's true that the streetlife around the Barbès-Rochechouart metro station is lively. I didn't find it to be loud at all, but I quickly found routes home that allowed me to avoid walking along Blvd de la Chapelle: if you're walking, angle yourself so you go up rue Guy Patin and it'll shoot you out right in front of the apartment. Otherwise, if you take the right exit out of Barbès-Rochechouart metro you'll find yourself equally right in front of the apartment.
It was really convenient for me to get where I needed to go. The apartment is right in front of the 4 line on the metro, which is the most important north-south metro line in Paris and will take you to all the major transportation hubs, like Gare du Nord, Les Halles, Chatelet, and Saint-Michel. From each of those hubs, you can easily go everywhere you need to whether you're at Paris for work or play.