This is a fantastic apartment for having central access to some of the major attraction in Paris: you are literally behind the Center Pompidou (modern arts), at the edge of the Marais, walking distance to the Louvre and Notre Dame. (Highly recommend a Batobus 2day ticket if you are visiting for 2days+). We had perfect space for 2 adults and 2kids and having the washer/dryer on-site was a huge plus. A tiny supermarket at corner of the street and artisanal baker (their formule midi is unbeatable) make it even easier to plan your meals.
Within the apartment, everything is newly renovated (imagine an IKEA catalogue) and functional. Coffee, tea and some basic food staples available. Super accessible host and willing to help.
As a warning: the stairs to reach this 4th floor (US counting) apartment are old, wooden, and sloping. An elevator can accommodate a luggage and a person, but is available AFTER you have already gone up a flight of stairs. Is it a deal breaker? No, but with two piece of checked-in luggage it was a lot.
There is also no air conditioning, but we did not feel we needed it the week we spent here: enough airflow by opening the windows to the street and the internal shute. I can imagine it might be more challenging when the heatwave hits.
All that said, we really enjoyed our stay and will not stay again at next visit, but also highly recommend.