The Route Napoléon leads eventually to SISTERON, 25km northwest of Digne as the crow flies, and the most important mountain gateway to Provence. The site has been fortified since time immemorial and even now, half destroyed by the Anglo-American bombardment of 1944, its Citadel stands as a fearsome sentinel over the city and the solitary bridge across the River Durance.
A visit to the Citadel (daily: AprilJune & Sept to mid-Nov 9am6pm; July & Aug 9am7.30pm; €4.60) can easily take up half a day. There are no guides, just recordings in French attempting to recreate historic moments, such as Napoléon's march, of course, and the imprisonment in 1639 of Jan Kazimierz, the future king of Poland. Most of the extant defences were constructed after the Wars of Religion, and added to a century later by Vauban when Sisteron was a front-line fort against neighbouring Savoy. The eleventh-century castle was destroyed in the mid-thirteenth century during a pogrom against the local Jewish population.
The best views are from the Guérite du Diable lookout post. The outcrop on which the Citadel sits abruptly stops here, 500m above the narrow passage of the Durance. In July and August, the festival known as Nuits de la Citadelle has open-air performances of music, drama and dance in the Citadel grounds. There is also a historical museum with a room dedicated to Napoléon, and temporary art exhibitions in the vertiginous late medieval chapel, Notre-Dame-du-Château, restored to its Gothic glory and given very beautiful subdued stained-glass windows in the 1970s.
Back in Sisteron's old town, you'll see three huge towers, which belonged to the ramparts built in 1370. Beside them is the Cathédrale Notre-Dame-des-Pommiers, a well-proportioned twelfth-century church whose entryway is flanked by marble columns, but whose interior contains nothing of interest. From the cathedral, rue Deleuze leads to place de l'Horloge, where the Wednesday and Saturday market is held and which, on the second Saturday of every month, hosts a fair.
Arriving by train at Sisteron, turn right out of the gare SNCF along avenue de la Libération until you reach place de la République, where you'll find the tourist office (July & Aug MonSat 9am7pm, Sun 10amnoon & 25pm; SeptJune MonSat 9amnoon & 25pm; tel 04.92.61.12.03, www.sisteron.com) and the gare routière. The genteel and old-fashioned Grand Hôtel du Cours on allée de Verdon (tel 04.92.61.04.51, fax 04.92.61.41.73; €5570; closed DecFeb) is the best hotel in town. For cheaper rooms, head for La Citadelle. Sisteron's four-star campsite is across the river and 3km along the D951 (tel 04.92.61.19.69; closed NovFeb; €10 for two people and a tent).
The food in Sisteron's restaurants is nothing special, though the view down the valley from the terrace of the Hôtel-Restaurant de la Citadelle, 126 rue Saunerie, certainly is (tel 04.92.61.13.52, fax 04.92.61.06.39; under €30). Le Cours, on the allée de Verdon (tel 04.92.61.00.50), serves copious meals, with the renowned gigot d'agneau de Sisteron included on a €19.50 menu, and you'll find plenty of eating places along rue Saunerie and on the squares around the clock tower. Le Mondial bar, on the left at the top of rue Droite, stays open late, as does L'Horloge on place de l'Horloge. Finally, if you fancy a swim, there's a large artificial lake between the allée de Verdon and the river.