It is located on a hill (220m) and from there the sightseeing is great. To the West, Nice lies at your feet. East, that's Villefranche and its natural harbour. To the South, an endless view on the sea. The outside of the fort, quite impressive, and the sightseeing alone are worth going there.
The ancient strongholds in front of the fort don't exist any longer. They were destroyed by Louis the 14th 's order. But the fort itself is immaculate and represents a very rare exemple of 16th century fortification.
To visit the inside of the fort, it is more complicated. It is usually closed and you have to request the visit to the city hall. The fort might become an exhibition center for modern art in the future. Inside, you'll see the storage facilities (underground), the officers living quarters, the chapell and the artillery platform.
Going to the fort is not convenient. By car you have to take the "Moyenne Corniche" and make a right (if you're going upward) in the little street 100m before you get to the Villefranche pass (route forestière du Mont Boron). It will take you to the Mount Boron frm where you can then go to the Mt Alban. Beware, it is narrow. If you're brave enough, you can walk, at least from the Mt Boron.
Use the map above to help you locate these places.