On the 5th with elevator. Calm and bright. oriented east. 
Real 140/190 bed. 
A extra folding mattress is available for a kid (60 cm X 180 cm) for a one or two nights stay.
The bathroom is small. It is not suitable for very tall people.  It's a nice little studio, very simple. not modern which must be kept very clean.
Metro Sentier, foodie district, 
fiber internet.
Air conditionning