In years past I have been fortunate to have had the opportunity to explore many areas of France: Paris, Normandy, Provence, Cote D'Azure and the Loire Valle, each of which was lovely and had its own charm. Recently I encountered the French Alps for the first time and was awestruck by its vistas, quaint villages and sheer genius of the engineering feat it took to traverse those mountains.
As a cautionary tale I would advise any who make that trip to allow twice as much time for the drive as you think necessary. It is very deceiving to look at a road map and think the short mileage from point A to point B can be traveled as quickly as one would on flat, straight highways. You want to allow time to stop and drink in the views or have coffee or tea at an outdoor bistro. You'll also want a break from having to pay close attention to hairpin curves on a narrow road that often does not have side rails to break your fall should you get to close to the edge!
Briancon was founded by the Romans and then became a medieval walled city. It's the highest town in Europe. We spent a morning walking around, discovering its many treasures and reveling in its quiet atmosphere. It has a gargouille, what they call a canal but is simply a very narrow trough of water you can step across that runs down the center of two different streets in Briancon. There's only one other town in France that has gargouille.
The spectacular part of the Haute Alpes that you drive through is the route of the Tour de France and it is hard to believe that all this gorgeous scenery is wasted on the cyclists. If they are looking at the beautiful views they're likely to run off the road into oblivion! Those roads are full of switchbacks and the grade is punishing, even in a car. It gave me a new appreciation of the athleticism of the cyclists.