By foot from Cannes to Cannes (city)
Cruise ships can't dock in the port of Cannes and will anchor in the bay. You come ashore in the old port by tender boat. From there it is easy to further explore Cannes on foot. From the parking lot near the tender boat stationthe historic center is well indicated.
For the Palais de Festivals keep on walking close to the harbor. Ther you will find a Tourist Office. If you plan an excursion outside Cannes, you have a few good options by public transport. Both the bus and train station are within walking distance from the port.