This is a great stretch of road. I was travelling from Castellane up to Briancon (the highest village in Europe allegedly) I took a detour and discovered the magnificent Lac Serre-Poncon. We stopped for lunch at the Volantis Hotel & Bar. It was their very first day of business, so to celebrate they gave us free drinks, it doesnt get much better than that. I have attached a picture which is the view from the terrace of the Volantis, which can be found inSaint Vincent les Forts. It is run by a dutch couple, lovely people !!! They have a paragliding school next door, you can just make the parachute out in this photo.
Beautiful scenery as the road twists and turns alongside the bright blue lake, the southern half is particularly spectacular. The northern half doesnt have so many drops off the edge so is the safer bit if you fancy a play. Highly recommended. From the D900 at St Vincent les Forts (a name on a map with nothing there!) you get a spectacular view of the road you have either just ridden or are about to ride depending on which way you are going.