The location of Claire's apartment in Le Marais was very close to public transit, close to buses to go to the Louvre and other central places, and also close to amazing bakeries, restaurants, and shops! We had a great time, and the couple times we were out late, we still felt safe in the area. The apartment itself is in quiet space off a bustling street, and Claire clearly has prioritized the safety of how safe guests feel in the space.
The space itself is equipped in a basic fashion, with everything a traveler would need (no laundry detergent was the only thing that came up). It's modern, clean, and bright, and comfortable for the two of us that were there. Loved the stay! Would absolutely recommend for the next couple (partners or friends) looking for a central place to spend a few days in Paris.