British Field Marshal Harold Alexander who was Supreme Allied Commander in the Mediterranean theatre established a military government in the north under plans already agreed by the British and American governments.
French forces were permitted by the Allies to penetrate Italy to a depth of 30 kilometres (19 mi) following the Axis collapse in May 1945, although in some places they violated this permission and penetrated much further.
After the war, Alexander ordered General Paul-André Doyen to withdraw the Armée des Alpes behind the Franco-Italian border but the general under orders from de Gaulle refused.

In messages between the Combined Chiefs of Staff it was reported that General Doyen had threatened to prevent the setting up of the Allied Military Government in Aosta claiming that his orders came from de Gaulle's provisional French Government.
American president Truman appealed directly to de Gaulle warning him that under the circumstances he had no choice but to cut off US military supplies and ammunition but would continue to provide rations.
French General Juin arrived the next day at Alexander's headquarters in order to clear up any misunderstanding.
It was agreed that the French would immediately withdraw from Val d'Aosta and Susa but would delay their withdrawal from Tende in order to save face because a hasty withdrawal would be most hurtful to French amour-propre.
The last French soldiers withdrew from Ventimiglia a month later.

This was the final act of the Italian campaign.
British Field Marshal Harold Alexander who was Supreme Allied Commander in the Mediterranean theatre established a military government in the north under plans already agreed by the British and American governments. French forces were permitted by the Allies to penetrate Italy to a depth of 30 kilometres (19 mi) following the Axis collapse in May 1945, although in some places they violated this permission and penetrated much further. After the war, Alexander ordered General Paul-André Doyen to withdraw the Armée des Alpes behind the Franco-Italian border but the general under orders from de Gaulle refused.
In messages between the Combined Chiefs of Staff it was reported that General Doyen had threatened to prevent the setting up of the Allied Military Government in Aosta claiming that his orders came from de Gaulle's provisional French Government. American president Truman appealed directly to de Gaulle warning him that under the circumstances he had no choice but to cut off US military supplies and ammunition but would continue to provide rations. French General Juin arrived the next day at Alexander's headquarters in order to clear up any misunderstanding. It was agreed that the French would immediately withdraw from Val d'Aosta and Susa but would delay their withdrawal from Tende in order to save face because a hasty withdrawal would be most hurtful to French amour-propre. The last French soldiers withdrew from Ventimiglia a month later.
This was the final act of the Italian campaign.
Second Battle of the Alps