Sonia’s appartment is spacious and convenient. A tiny elevator takes you to the sixth floor if you don’t want or are unable to take the stairs. It has two bedrooms, which was good for our company - familiy of 4. Sonia lets you use the appartment as if it were yours. Small minus is the bathroom, where you have to hold the showerhead above your head yourself. Why not hang it a bit higer?
The location is good if you want to explore Montmartre on foot or the area around the appartment. Public transport is close, but we mainly used our bicycles. We left them in the street at night, which proved to be safe. With our two children (11 & 13) it was easy to get around Paris by bike. They are used to cycling in their hometown though (still, that is nothing like traffic in Paris). It’s faster, easier and more fun than the metro or the bus. But we made a metro ride to show them the coolest stations as well :-).
We didn’t meet Sonia in person, but she communicated easily and was able to quickly solve a little problem with the keys when we arrived. No harm there.
Would go back to this place if we went again!