We booked Alberto's apartment for a few days in our trip to Paris. We did the reservation the day we arrived and Alberto was always very responsive and let us get in immediatly.
Although the house is in a 6th floor without elevator, and the toilet is outside the apartment (the shower is inside, but we haver never crossed with any other person in the toilet, so it was ok for us).
The house is well located and close to a metro station and it was a good option to Stay in Paris.