Beautiful apartment, highly recommended. Very near the Gaite metro stop, and not far from Denfert Rochereau---the location is extremely well connected to the Parisian mass transit network. The apartment has two floors and is in the top floor of an apartment building; the view out of the top floor is a fun jumble of chimneys, top floor French balconies, and rooftops. You can also spot the Tour Montparnasse. The Rue Daguerre is full of little shops and markets, making this apartment a great base to explore Paris.
As I imagine is typical among Parisian apartments, the apartment is a bit snug. The top floor (bathroom, bedroom) is built into the roof and has a slanted ceiling; the bottom floor's ceiling is also low. At 6', I had no problems in the apartment, but anyone significantly taller than that should expect a lot of crouching.