Very nice apartment in the heart of Paris situated in a lively (but not loud!) neighborhood with lots of cool and hip shops, bakeries, groceries etc. Léopold is a very kind host and his apartment is full of books so you won't get bored (if you speak french). Very nice, fully equipped kitchen and two big french windows towards the courtyard (so its not noisy at all). 10/10 can recommend.
PS: Be aware that its on the 5th floor, no lift. But didn't you plan to exercise a bit more, anyways?