My friend and I stayed there for 4 nights in a room with a double bed. It was smaller but it was clean and the bed was comfortable. You can hear the street traffic a little through the windows after 7am, but it wasn't overly noisy by any means. The hotel is located in a safe, neighborhood area. The Pernety metro stop is literally right around the corner from the hotel so that was really convenient. The hotel staff was overall very friendly, although the one lady had a slight bit of attitude. The internet was not working but there was an internet cafe at the next block. The breakfast was good and overall it was a great stay. I'd highly recommend it.
The photos of the hotel are misleading as they show rooms much more spacious than in reality.
The quality of the linen, furniture is just acceptable.
What made this hotel 3 stars?
Not a bad little hotel, but I'm a little surprised it got three stars. The rooms, while very clean, are very small with only the level of comfort I'd expect from a two-star. However, the staff was exceptionally courteous and helpful. The location is really incredible, literally next door to the Pernety metro stop, which makes it easy to get anywhere in Paris quickly. It's within walking distance of the Montparnasse train station and tower (or two stops on the Metro).
Given that the prices are very affordable, it's potentially a great deal. Don't choose this place if you want luxury or exceptional comfort, but if you just want a simple bed in a clean room in a very convenient location, you can't go wrong.
One tip: ask for a first-floor room if you want wireless Internet access. It's provided (for a fee) from Orange.fr and works great, but only from the first floor.