The apartment is in an amazing location! Lots of great places to eat and drink nearby. It's also close to the Metro--it was easy to get to (from Montparnasse Station) and to leave to the airport.
The apartment itself was a bit underwhelming. We didn't like the bed: it had a thin, futon-like mattress that was hard and unpleasant. The living/dining room could do with some more comfortable places to sit.
This didn't bother us, but the bustling restaurant on the ground floor means it can be noisy at night, something to be aware of if you're looking for quiet, early evenings.