We had a really good experience staying at Sonia's place. Although the 6 flights of stairs caused some deep thought regarding everything that was in my pockets so i wouldn't forget anything ( i forgot my cell phone one day and that was a drag, but I'm a 55 year old American) The upside of this however is that you are in a top floor apartment in the middle of Paris which means views and very little if any street noise. We utilized the kitchen a bit which helped with the high cost of Parisian living. Good location - walkable from both the gar du nord and the gar du est.