King Salman is expected to vacation soon at the mansion that sits above an isolated but public beach near Juan-les-Pins.
Despite protests, the region's state official, Philippe Castanet, said the beach would be temporarily closed if the king visits which regional security chief Francois-Xavier Lauch said is nearly certain.
Lauch said by telephone today that boats would also be banned from plying the Mediterranean near the mansion.
Last week, angry beachgoers won a temporary halt to unauthorized work ahead of the royal visit, notably a cement slab on the sand for an elevator allowing direct beach access from the mansion.