After the capture of Cherbourg, the 7th Panzer Division is ordered to Rennes, there to play its part in the final operations in Brittany.

Rommel writes to his wife:

Rennes, June 21st, 1940

Reached here without difficulty. The war has become practically a lightning Tour de France. Within a few days it will be over for good. The local people are relieved to see everything happening so peacefully.

Morlaix and Lorient fall during the day. In Brest, Hoth's armor has been relieved by standard infantry units. The town is a scene of desolation. The harbor is empty. Ships that have been unable to put to sea have been scuttled. The dockyard is a heap of rubble.

By evening the whole of Brittany has been occupied by the Germans.

But the main event of the day, from the point of view of military operations, is the launching of a fierce offensive in the Alps. At dawn, 19 of the 32 Italian divisions massed in the sector storm the French positions.

The French High Command had drawn so heavily on the Alpine Army in the past few weeks that it is down to skeleton size. France's defenses in the area take the form of three fortified sectors:

• 1. In the north: the fortified sector of Savoy;
• 2. In the center: the fortified sector of Dauphiné
• 3. In the south: the fortified sector of the Alpes-Maritimes.

These are manned by fortress units and by three Class 'B' divisions: the 64th, 65th and 66th Divisions.

The French are in a difficult position from the very first, for even as the Italians attack from the east the Germans are sweeping down the Rhône valley to take them from the rear. Gen René-Henri Olry responds swiftly and decisively by splitting his forces into two groups. The first, facing northwestward, is to meet the German advance; the second, facing southeastward, will deal with the Italians.

The latter are exerting pressure all along the line. In the north twelve battalions try to capture Bourg-Saint-Maurice, advancing via the Seigne, the Petit Saint-Bernard, and the Mont passes, but they only manage to surround a small fortified post near the Petit Saint-Bernard pass, and even that they can not take. Yet the French positions are held by only four battalions and 44 guns.

In Maurienne the Italians attack in force. Their objective is Modane, which they strive to reach by way of the Mont-Cenis, Sollières, Bellecombe and Clapier passes.

At 5:30am more than a thousand shells begin landing on the La Turra fort, but it continues to resist stoutly. Farther south, however, some French reconnaissance groups are outflanked by 2 battalions and driven back from Le Planey to the La Tuille dam.

In Briançon there is an artillery duel between the Italian fort at Chaberton and a battery of French 280s. Within hours Chaberton is compelled to cease fire, every gun having been put out of action.

At the end of the day the Italians are being held all along the line, except on the Le Queyras headland where they have managed to encircle to village of Abriès.

In the evening, to counteract the possible consequences of German thrusts on either side of the Massif Central, the French High Command orders the 16th and 19th Districts to form defense groups to cover Toulouse from the east and Bordeaux from the north.