This is a great place to stay for 2 or 3 people. Here are some specifics:
The location is in a modern, large apartment building next to the Montparnasse station. Normally there are excellent train, taxi and metro connections that will get you to pretty much any place in Paris without much trouble. We were there during the rail and metro strike in December, so trains and metros almost completely not working. In spite of this, this location was close in enough that we had no trouble walking to Palais Garnier, the Orsay and Louver, the Marais area, Ile de la Cite, Saint Germain, San Michele, the Eiffle Tower and even the Sacre-Coeur church, although that last one was a bit of a hike.
There are plenty of restaurants, grocery stores, fast food places and interesting shopping in the immediate area.
The building where the apartment is located feels very secure, and there is a large park with a very nice kids playground immediately adjacent to and accessible from the building.
The apartment was clean and well equipped. The one bathroom was fine. The shower in the bathtub had plenty of hot water and everything worked well.
There is a queen size bed in a bedroom with a door. The bedroom is private and the bed is very comfortable. There is a couch in the main room which pulls out into a single bed, which was also comfortable. The kitchen was small but well equipped and everything worked fine. The apartment wall is completely windows in the kitchen, main room and bedroom. The view of Paris is great and it is very nice to have the light.
Do and Jean-Marie were responsive and easy to work with.
In summary, we really liked this apartment and location and price. If we come back to Paris with 2 or three people, we will definitely stay here again.