Nice's Cliff Walk follows the rocky edge between the old town headland and the port, trading the grand sweep of the Promenade des Anglais for something tighter and saltier. The path is short, but it gives you a different angle on the city: limestone, clear water, moored boats, and the curve of the Baie des Anges behind you.
It is best as a connector, not an expedition. Walk it between Castle Hill and the port, pausing for the sea views, then continue into the harbour streets or back toward the old town for lunch.