Leo's place is in a wonderful Paris neighborhood - Le Marais - we had a wonderful time exploring the area during our stay. It's within a short walking distance of at least 3 Metro stops, and less than 10 minutes from the Seine. There are countless cafes, bistros, and shops in all directions. The street itself is pretty quiet - there was virtually no noise from the street or other tenants throughout our stay.
The flat itself has the typical accommodations - bed, bathroom, shower/tub, kitchenette, and table. It's a fairly simple accommodation, but it worked perfectly for my wife and I - since we spent so much time out and about, this worked perfectly as a "base camp" for our time in the city. The unit also has a fridge, stove, toaster, and French press, so it works nicely to eat a quick breakfast or snack in the unit before or after you take off for the day.