If you're going to Paris for a romantic getaway or for a dive in the Parisian "vie", this is the apartment for you. The view is unbelievable, doesn't make you unhappy to get back home at all! Metros and bus are very close to the apartment, if you'll buy a Navigo you won't have problem and will get almost everywhere in a short time.
Montmartre is a great neighborhood and you will discover it also thanks to Antonin and Pierre's great suggestions. We never met them, but they were available and kind all the time and also very flexible about check in and check out!
Yes, the apartment is small, but bigger then most of Paris' studio! Share it with someone you're comfortable with and you won't have any problem. In less words: take it, 'cos IT'S A CATCH!