If you want to be in the center of Paris nothing beats this location, a charming walk from the Ile St Louis and several metros, and right across the river from Le Marais, St Germain-des-Pres and loads of other neighborhoods and sites. Very touristy but very central. It's beautiful to look out on the Seine but also noisy, and the bedrooms face that way--tourist boats with loudspeakers, sirens, musicians on the bridge, etc. The building is lovely, feels safe and accessible, and so nice that it has a lift.
The flat itself is quirky, no other word for it. Upsides: Plenty of light and left pretty clean (though understocked with toilet paper and dish soap--we had to go out and buy our own). The beds are suitably comfy with plenty of blankets, at least for the August weather of our visit. Good shower. Nice cross breeze.
Downsides: absolutely awful living room furniture--so uncomfortable we never wanted to spend any time in there. We actually had to laugh at how uncomfortable every single seat in the living room was. The kitchen is not great and we never ended up cooking even once. The wifi worked perfectly in ONE bedroom, and everywhere else in the apartment was terrible. This was a big problem as we were there for two weeks and I needed to work and for this price, there should be great wifi. This wasn't even decent outside of the one space. The bedrooms are not private from one another, which the ad should make clearer. And there's a lot you can't touch and can't use and can't open, as other reviews have mentioned, which isn't exactly homey and it was lucky only one of us--me--needed a usable closet to hang clothes. Bottom line is there is a lot that could be done to improve this sweet place.