We stayed at Marco's place for a month and loved it!
Marco and Frederico were very helpful/flexible and went above and beyond to help us with whatever we needed.
The place is ideally located—walkable to everything, next to three different metro lines, and in the heart of the beautiful center of Paris. The apartment is on the 5th floor with no elevator, which is part of the charm you have to embrace! (A previous review mentioned it's on the 6th floor, but that's for American standards, not European/French, where they count the walk-in floor as floor zero)
The apartment itself has everything you need. There are lots of extra small stools/small tables that can work as a desk/coffee table that was perfect for working from home!
Please understand this is an OLD place. It has "character" along with all the other old buildings in the area. If you need everything perfect, I would point you to a more modern/charmless building.
We would definitely stay here again!