Pros: in the heart of the Marais, great shops, cafes, restaurants. The Bastille around the corner, the Ile St Louis a 20-minute walk. The apartment is on a convenient though nondescript alleyway, very clean, with a nice kitchen, good light in the living room, comfortable sofas. The shower (located in the smaller bedroom) is excellent.
Cons: the book of information left for guests is outdated. The person listed as the person to call for help was not actually reachable by either phone or email (whoever was at the phone number yelled at me in French and then hung up). TV impossible to work, not a big deal for us but might be for some. It was blazing hot during the week we were there, with not a fan in the apartment. An alarm went off day and night for our first 24 hours before we realized it was the fridge (not a word about this in the manual). The apartment is very loud--noise from the boulevard half a block over, from other apartments echoing through the air shaft and the roof deck next door. Walls thin enough that I could hear my daughter's phone vibrate if she got a text in the next bedroom. The disco ball lighting in the bathroom was loved by my 16 year old daughter but I got a bit tired of it after a couple of days :).
All in all an interesting place, not a terrible stay at all but suited for the more adventurous.