We spent more than a week here and were very comfortable. It felt like our home in Paris. Martine met us at the front door upon arrival and familiarized us with the building and the apartment.
We already knew the area, as we had stayed nearby a couple of times. There are lots of shops and restaurants nearby, as is La Motte-Piquet - Grenelle station with 3 metro lines. The Champ du Mars is 3 blocks away.
Best of all on Sunday and Wednesday mornings there is a market on Rue Grenelle, just a couple of minutes away. The kitchen is fairly basic but we had no problem preparing some fabulous meals (the ingredients helped).
Upon departure Martine arranged our transfer to Gare du Nord. I would stay here again.