This is a great option for a family looking for more beds and a second bath in their rental. Our teens liked being able to have their own space downstairs and it was nice to not have to share a single bath. Given the quirky layout of the basement steps, it would likely only work well for older kids and agile adults.
As others have mentioned, this unit is on a side street in a great area with lots of restaurants and amenities. The restaurant Pain Vin Fromage is on this street and it is excellent for fondue. The metro station is very close, but note that it is not a main line and you will have to transfer to get to most places you will want to go. Not a big deal, but worth noting.
The space was comfortable for a group of 4, but larger groups planning to eat some meals in should know there is only one small table to eat at with seating for 3. The main bed backs up to a window that is street-level. We ended up using earplugs and a white noise app to get a better nights sleep.
All in all, this was a fine option for a Paris “home base” and I think the value was good for the area and having two baths and three beds.