Isabelle was helpful and communicated with me before the booking and met us at the apartment to show us everything. The apartment itself is perfectly situated, with Sacré-Cœur a short walk (or funicular ride) away, a metro station within 5 minutes walk and Gare du Nord within a 10 minute walk. Isabelle did warn us that the main road can get a little loud but, having stayed in November and kept the windows at the front of the apartment closed, we didn't notice the traffic noise at all! As other reviewers have noted, you were more likely to hear the squeaky floorboards, but this wasn't all that much of an issue really. Everyone in our group of 5 absolutely adored this apartment and we leave with fond memories of both it and the surrounding areas (can definitely recommend 'Pain Pain' around the corner for a breakfast pastry or sweet treats!). A great base from which to explore the city of Paris!
Oh, and every Airbnb should come with a piano as beautiful as the one in this apartment (it played just softly enough that you felt as if the neighbours probably couldn't hear much of what you were playing!)!