Dominique's flat was in a perfect location, near the Luxembourg Gardens and the Pantheon. The RER Luxembourg stop was a 5 minute stroll/3 minute power walk away, which really added to the convenience. One stop to Notre Dame, two stops to the Louve, three stops to Gare du Nord, and direct connection to both airports. Make sure to get into the north end of the train to shorten the walk to Dominique's flat.
The streets around the unit were clean for Paris, and relatively quiet. The surrounding streets don't see many automobiles, so there wasn't much car noise. There is a restaurant down the block and opposite two of the bedrooms. If you're sensitive to noise, them closing down at 11pm could be annoying, but it didn't bother us. Otherwise, there are patisseries and restaurants a-plenty within walking distance.
As for the unit itself, it was clearly lived-in but clean. Our party comprised of 5 adults (2 couples) in the 3 bedrooms, and there was plenty of space for us all. We also used the in-unit laundry machine, which worked perfectly. Our visit was during summer, and there is no A/C. However, nights were cool enough that opening all the windows made it quite comfortable.
Overall, we had a great time, and would definitely stay again if we find ourselves in Paris again.