Hélène is a really nice person, very flexible and you can always reach her when needed. Communication is fast and clear. Our flight arrived very early and departed quite late and this was no problem at all with checking in and out. The house is big, nice and quiet. The balcony is perfect, but since it was 34 degrees when we were here we only sat there in the evening. Neighborhood is also quiet and yet has everything you need on site.
The only thing I missed (and I already said it to Hélène) was a possibility to listen music from phone or ipod. A simple audio jack would fix it. We went a few days to Berlin Atonal festival and it would have been nice if we could re-listen some things at home. But this wasn't a big disaster at all since you're not staying home for days. Overall, i would totally recommend this place and :)