My girlfriend and I stayed 5 days at Sonias place, which is centrally located and well equipped. The bed is a proper matress, not a couch like in the pictures. It could be a little bit bigger (I think it is 1,20x190m), but it worked out for us. The linen we found on the bed were washed but had some stains on it that the washing machine obviously couldn't deal with. But we found another pair in the wardrobe, so no problem there.

The balcony has a nice view of the eiffel tower, to see Sacre Coeur you'll have to lean over the railing.