Super fun! Great location, clean, neat, had everything we needed and everything worked well. The unit is a prior storefront in Passage Choiseul -- weird and wonderful. The conversion is brilliant -- roomy, light, airy and very, very quiet.
The location is amazing -- around the corner from Operá, <10 min walk to Louvre, 18 min walk to D'Orsay, <25 min walk to Notre Dame or, in the other direction, <25 min walk to Champs Elyses. Great Metro access to several lines.
Lively neighborhood that is a mini-hub for Japanese and other Asian restaurants. Use the Palais Royal gardens as your route as much as possible -- super pleasant to cut through on your way in and out.
NOTE: There are 5.5 levels to the apartment and a narrow-ish stair connects them. They are a bit uneven so it's not suitable for anyone with anything more than minor mobility issues.