The location is good - three minutes walk to Luxembourg Gardens (the park and the metro station), quite a few restaurants, groceries, boulangeries and pharmacies around. Very historic atmosphere (we saw a XIX century movie shooting just around the corner). The street is pretty quiet (one-way traffic). Though there is a night bar across the narrow street open from 5 pm to 2 am. Was not a big issue with the balcony closed, but you can hear the talk and music.
The apartment is tidy, not big - it's one small living room and one bedroom, was just enough space to place our luggage and sleep (two grownups and one kid). Dining was fantastic on the big open terrace (no cover, though, for rainy days). Best to stay for 3-4 days. On the fifth day it seemed too small with all our luggage and newly bought things.
And many thanks to the hosts for fast communication.