The existing reviews from David and Felicity, Christine, Deborah, Freya, and Ronald are all spot on!
It's a phenomenal location - located on a small alley just off the bustle of the main streets in the Latin Quarter, it was incredibly convenient for walking home late in the evening from dinner. It's definitely a better fit for people that are sure footed and aren't tall or wide, as access to the bathroom and bedroom is via a narrow and steep spiral staircase. It might be a challenge living in the apartment long term, but it was a great adventure for a couple in Paris for a romantic week. We loved the skylights in the bedroom and bathroom, opening them to get fresh air at night, and looking out through them to see the Paris skyline and sunsets.
We concur with Freya that the shower temperature was definitely on the hot side and that the disposable sheets were not the most comfortable. That said, the memory that sticks with us is the location and overall charm of the apartment.
A few finds in the neighborhood - Strada Cafe on Rue Monge was great for morning coffee and breakfast, and Le Vieux Bistrot was a treat for dinner.