It was an excellent home base for us to explore Nice and the Cote d'Azur region. All 5 stars.
The flat is very comfortable and well-appointed, with great sea views. It's in the heart of "old town" -- most of which is dedicated to pedestrians -- and close to the shoreline promenade and beach. Good bathrooms, bedrooms, and comfy beds, and a nice living room. The kitchen is well equipped with quality appliances and everything you need for cooking and eating, and right downstairs is the Cours Saleya market with fresh produce almost everyday, plus all the restaurants and great food available in old town. The host (Delia) is great -- friendly, communicative, and responsive.
You should note that while the flat itself is very modern and clean, it's in an older building, and there are 60+ well-worn steps to your door -- not a problem for us but could be for some. Also, the location has great nightlife on the street below, with music and revelry into the early hours. The flat has thick walls and good windows, so the noise is not too bad, but you will still hear it most nights.