Yankel's apartment was truly perfect for us. It was very clean and, despite being compact, was very comfortable and well proportioned for my husband and I. The location is amazing!! We were only in Paris for 3 nights so it was so great to be able to walk easily to all the sights and there was a little store right next door where we get all the bits we needed. We didn't ever get to meet Yankel sadly but that was mostly because his communication was so clear and thoughtful and because there was nothing wrong anywhere in the apartment!
The only note I'd make is that it is a small apartment which was fabulous for two but I would only return with a couple if I knew them very well and felt comfortable with them as you would share a small space. And I would also second the other reviews in that it is on the fifth floor (sixth floor for North American travellers) so any visitor with accessibility requirements should be aware of that.
Overall, great apartment, fantastic location - would definitely recommend!!