Christophe is very responsive (French and English). And the apartment is fantastic (cozy with lots of character).
The space feels bigger than the pictures show. The vaulted ceiling has a skylight letting in an abundance of sun. A large double window opens and overlooks a courtyard (very quiet/peaceful).
There is lots of storage space, leaving the living area for enjoyment or work. The internet is fast and I got great cell reception.
You get a separate bed/sleeping loft (in addition to the couch sleeper) making this place more like a one bedroom to me compared to other studios. The kitchen has a dishwasher and a vent fan over the stove that removes the cooking exhaust out of the apartment. The bathroom is tucked away and includes a washer and a dryer (rare in Paris); a powerful shower with lots of hot water; and a separate heater.
The location is perfect. It is a short walk to the Jussieu metro stop, the botanical garden, the Panthéon, the Seine, Lutèce, and Rue Mouffetard.