Le port de Nice
The harbour is located East of the city.
If you come from Corsica with a ferry, the wharf is located at the end of the harbour (down right, blue logo) and if you don't have a car you will have to walk 10 mn to bypass the bassins and find yourself in town with bus lines. You can also take the buses in this street, but there are not many of them, or call a cab, or rent a bike (a vélo bleu station is located boulevard Stalingrad, ahead after the harbour exit for the cars, a few dozens of meters away).
If you come with your own boat and find a place in the Port Lympia, you'll be closer from public transportation.