Sonia's apartment is in a superb location. Right next to the beautiful Canal Saint-Martin, many Restaurants and Bars, a ten minutes' walk from the stations Nord and Est and just above a super market. Still it is quiet as her room is orientated towards the courtyard.
Take note that the internet connection isn't very stable. We often found ourselves standing in the hallway were the reception is much better.
But aside from that (minor) issue, we felt really comfortable and enjoyed our stay!