I had a pleasant stay at Julien's place. For the price, it is very worth it. My only real complaint is that the kitchen area was a bit dusty and the dishes were dirty. The wifi is also a bit slow/unstable in case you care about that.
Everything else was just as we expected. The room is very small but cozy, the location is excellent and the bed is super comfortable. If you're looking for a room to simply rest at night after a long day of exploring Paris, this is the perfect place.