Our stay at George and Silvie's appartment in late August was great. George arranged for us to be welcomed at the appartment and provides a nice booklet explaining all practicalities for the appartment.
The appartment was beautiful, very clean and well taken care off. It is located just near two metro stations (sentier and bonne nouvelle) and near many restaurants and shops. It is also in walking distance to centre Pompidou, Ile de la cite and les halles - for those who want to shop.
Only low point: If you come in summer expect it to be hot ;)