Tiny spot for a single traveler in central Paris. In terms of price and location, you really can't beat this!
You'll want to pack light (backpack or small carry-on suitcase) -- the spiral stairs, as others have pointed out, are challenging in that they're quite steep and narrow.
I appreciated that this was an actual person's home (as opposed to mega-airbnb operator/hotel, etc) and has the small touches of someone who's truly spent time there.