The Map below shows the surrounding of Saint-Cézaire sur Siagne, a charming medieval village of the Alpes-Maritimes département. It hangs over the Siagne river, that forms a natural limit with the neighbouring Var département.
But you can take the bus from Grasse, line 520. 

Itinerary from Var : (Marseille - Toulon)

On the A8 motorway, exit at the "Les Adrets" junction and follow on the D37 road towards Fayence/Montauroux.
When you reach the N562 road, follow signs to Grasse/Peymeinade.
After approximately 8 Km (5 miles), get on the D2562 road towards Grasse/Peymeinade.
When you reach Val du tignet, get on the D11 road.
At Spéracédes, follow on the D13 road towards Saint-Cézaire/Grottes de Saint-Cézaire.

Itinerary from Alpes Maritimes : (Nice, Monaco, Italia)

Get out at the "Cannes" junction on the A8 motorway.
Follow directions to Grasse, along the RN85 main road.
After the tunnel, at the first roundabout, follow signs to Pégomas / Saint Jacques.
At the roundabout, follows signs to Grasse-Saint Jacques.
At the next roundabout, take the D2562 road heading to Draguignan.
At the roundabout, follow signs to Saint-Cézaire / Grottes de Saint-Cézaire on the D13 road.