Briançon is the sole subprefecture of the Hautes-Alpes department in the Provence-Alpes-Côte d'Azur region in Southeastern France. It is the …Briançon is the sole subprefecture of the Hautes-Alpes department in the Provence-Alpes-Côte d'Azur region in Southeastern France. It is the highest city in France at an altitude of 1,326 metres, based on the national definition as a community containing more than 2,000 inhabitants. Its most recent population estimate is 11,084 for the commune.