Mathieu was a great host. The unit was as described.
Engagement Process:
He was very communicative and timely with his responses. He provided great instructions on what to expect, how to contact him, and how to check in on day one. This is par for any great host, but he seems to be one of the best.
Local Area Information:
His guides were well written and informative. However, we tended to just resort to our smartphones or laptops. For Americans, be mindful that Yelp is not well used in Paris. You might have better luck with Google Maps and TripAdvisor's The Fork app for better local resource searches. A lot of sit down restaurants require reservations and "dinner" time appears to be closer to 8pm. There seems to be a lull in open restaurants between 3pm and 7pm. Sundays are a bit of a challenge to find open restaurants, but they definitely exist.
Markets:
Something to keep in mind for American guests - there are no large grocery chains. Don't expect that. Franprix, Monoprix, G20, and Carrefour City are all within walking distance and most appear to close around 9pm. If you do plan to grocery shop, bring a grocery bag as most do not appear to provide bags. If you are landing late, there is a tiny grocer that seems to be open late (11pm?) and on Sunday - le Marche de Jussieu aka le Petit Marche (per their awning). In general, I observed traditional fruit and vegetables seem to be readily available at all grocers, but the selection is limited in variety. If you are looking for unique varieties and selection, find a local farmers market instead.
Pharmacies:
I swear there is a pharmacy on every block. Look for the green crosses - I think there are five (5) or more in the neighborhood. If you don't speak French but you need something, be sure to bring along your smartphone for translation. As with most people and places, there is no guarantee that English is someone's strong 2nd language and when you need medicine it isn't the time to find that out and try your luck. Most people are friendly enough to provide assistance. My experience was positive.
Great Travel Hub:
The street is quiet but easily accessible within five (5) blocks to multiple markets/bodegas, restaurants, cafes, butcheries, etc. Even more convenient was the walking distance to Paris' metro stations - both Pasteur (<3 minutes) and Montparnasse (~10-15 minutes). If you are looking to access any of the major tourist locations, you are really less than 45 minutes away and maybe two (2) transfers from most. If you like quiet, but accessible, then Mathieu's place is definitely that. If you need the hustle and bustle of a major tourist area or business district you may want to look elsewhere. I enjoyed the slower pace of the neighborhood.
Unit Interior:
The space is well maintained. For most Americans, this space might feel a little different. You'll note this primarily in the bathroom and the kitchen. I am 6'1" (1.8 meters) tall and it took a little to get used to it, but they were minor and really nothing to complain about. As others have noted in their reviews, the second shower is a tight fit. During our stay, we did not use it.
The kitchen has the basics. You'll note that Mathieu has a European style washer/dryer in the kitchen next to the dishwasher. If you are not used to this, please read his instructions in the check in manual. Same with the dishwasher - the instructions are in the welcome pamphlet.
Unit Noise:
The walls and floor are a bit thin. You certainly can hear a lot of movement in the floors. Be mindful that as you might complain about others making noise, you are likely also making noise for others. The neighbors were friendly though. It definitely looks like this complex hosts several AirBnB units so you will see new tenants come and go with high frequency.
Conclusion:
Overall Mathieu was a great host and his unit was a great value. It had what we needed and it was ideally centrally located near a lot of things we wanted access to. I would rent it again.