Fortified Sector of the Dauphiné
The sector was extensively subdivided into informal districts, sub-sectors and quarters or quartiers, reflecting the fragmented nature of the Alpine landscape in which each valley was a distinct defensive entity.
Small units were employed to patrol the border and to man individual posts ranging from observation bunkers to excavated mountaintop artillery ouvrages.
The Italian Fort Chaberton presented a menace to the area with its heavy battery on a commanding 3,131-metre (10,272 ft) peak just across the border, 11.6 kilometres (7.2 mi) from Briançon.
These major Alpine positions were to be built by the Commission pour l'Organisation des Régions Fortifiées (CORF), the primary organization dedicated to the planning and funding of the Maginot Line.
Resources were soon diverted into fortifications for the SF Alpes-Maritimes to the south, and initial improvements were limited to a reconstruction of the old Fort du Janus.
The Col de Larche corridor was defended by the CORF-built gros ouvrage[nb 1] Roche-la-Croix, its upper battery and the Forts Tournoux and Viraysse, as well as a variety of CORF positions around Saint-Ours.
The Montgenèvre corridor was covered by the extensive network of forts around Briançon, centering on the renovated and expanded fortifications at Janus.
The 64th ID was made up of Class B reservists, not suited for sustained combat, under General de Saint-Vincent at Embrun.
[6] Command post at La Seyte, elements of the 72nd BAF Barracks for peacetime: A number of concrete emplacements were built by the Main d'Oeuvre Militaire (MOM) in the quarter.
[5] When Italy declared war on France on 10 June 1940, the French forces along the Alpine Line amounted to two corps constituting the Army of the Alps.
[7] Actions in the Briançon area were focused on the threat posed by the mountaintop batteries at the Italian Fort Chaberton, armed with eight 149mm guns in turrets.
The principal activity took place, as expected, in the vicinity of the Col de Larche, starting on 17 June with infantry patrols that were engaged by the artillery of Roche-la-Croix, producing heavy Italian casualties.
The bad weather continued on the 24th, but a sharp engagement on the Col Rémi and around Tête-Dure resulted in heavy Italian casualties and a number of prisoners.
The Italians had failed to accomplish any significant penetration of the frontier, but German forces had come down the valley of the Rhône and were operating to the rear of the Alpine Line.
[10] After mobilization the reorganized battalion held the Gondran-Aittes quarter, occupying ouvrages Janus, Gondran and Les Aittes.
Active-duty personnel were incorporated into the Vichy French bataillon départmental des Hautes-Alpes at Gap and a guard unit at Briançon.
With the Normandy landings, the French Resistance was instructed to impede German reinforcements from reaching northwest France by sabotaging the choke points through the Alps.
However, the Germans remained in the surrounding fortresses, and the 90th Panzergrenadier Division mounted an unsuccessful counterattack against American patrols and French forces, operating from the Fort du Randouillet.
The newly arrived 4th RTM and 3rd Moroccan under Colonel Molle mounted an offensive to drive the Germans over the Col de Montgenèvre starting on 4 September, and taking Gondran, Infernet, Croix-de-Bretagne, Chenaillet and Janus the same day.
Randouillet and the Fort des Têtes were captured on the 6th, but German forces on the crest of the Col de Montgenèvre continued to fire into Briançon.
The area around Les Fourches and Restfond was captured by French and American forces in late September, but was evacuated for the winter in October.
[13] As part of the Paris Peace Treaties of 1947, the Franco-Italian border was adjusted to place Mont Chaberton and the upper reaches of the Col de Larche in France.
