Delphine's apartment is absolutely the best for large groups! The apartment is truly stunning, and very spacious and inviting. There were 7 adults when we stayed and there was plenty of room for all of us (5 bedrooms and 3 full baths). The kitchen is also very well-stocked with supplies, which is great because we cooked here a few nights after some trips to the markets down the street. There is plenty of comfortable space to just relax in the light-filled apartment (since the apartment is on the 6th floor with windows all around the light just streams in).
The location is very convenient for sightseeing, and the neighborhood is safe, clean, and quiet in the evenings. There are lots of great shops, markets, cafes, and restaurants all around the neighborhood. I highly recommend walking down to the markets for fresh fruits, veggies, cheeses, and meats! We all walked to most tourist sites (we put on probably 6-10 miles a day), but the metro at the end of the street is convenient for longer trips. We were also there to attend a conference, and the apartment is an easy 15 minute walk to the conference center.
Delphine was wonderful and kept in communication with us the entire time. She is perfectly fluent in English (helpful for me!). When we needed anything, she responded immediately. She also put together a book for the apartment (including where to shop and eat), which is super helpful.
I can't recommend this apartment enough. I felt like I was able to experience Paris more like a Parisian in this beautiful apartment!