My stay at Hotel Aviatic was really great. The staff was friendly and the room was clean and matched more or less the sample room shown on the app. For the price of a night (around 60€), the services offered were more than what I expected. In fact, breakfast was included in the package. If you are looking for an affordable place near Montparnasse, Aviatic Hotel is the way to go. I will definitely recommend it to my friends visiting Paris.
I just wished they did have those door labels that say "do not disturb" or "please clean the room" to avoid the awkwardness of having the room service open your door even when locked :)