Sebastien's place has a great location. Easy walk to Notre Dame/Saint Chappelle, Louvre, D'Orsay, Luxembourg gardens, etc. Very quiet but area is full of good restaurants and hang-outs.
The place is small. I'm 5'10" and could not stand up fully in the shower.
Amenities are fine but not a place to spend extra time in because of the size.
Coffee for the nespresso machine provided only for first day. Machine is not a common size so was useless to us after day one of five.
Also, at check in we were told to clean the place before we left and that the cleaning fee was just for linens. We cleaned it but finding this out afterward was off-putting and unprofessional. if I'm doing the cleaning I'd expect a bit lower price also.
Overall had a nice time in Paris while staying here.