The apartment is charming and unique, tastefully decorated, and amazingly well located. We stayed for 4 nights in August with our 2 kids (a 3 and 6-year-old), and only regretted that we could not extend our stay for an additional day.
With plenty of good restaurants, boulangeries and shops just downstairs, we felt that we were in the perfect spot for our Paris vacation. The host was helpful and friendly and the whole experience flawless.
If you arrive by car, be prepared that there is virtually no parking or even stopping possible in front of the building, but a parking garage is very near by. Access to the apartment is through a very narrow and steep spiral stair, and the upper level of the duplex has another steep, open stair. There are plenty of seating areas but no dining table in the apartment, only 2 kitchen counter stools and a very low coffee table. But in a way these quirks added to the experience of staying in a real Parisian apartment and did not bother us. The apartment truly felt like a home away from home.