Italian OoB and main events :
Beside the naval events noted in this website a few notable things on the aerial events on the French side :
After Italy declared war against France, Farman 222.2, 223.3 and 223.4 heavy bombers and Lioré & Olivier 451 bombers dropped leaflets over Roma and bombed fuel refinery in Porto Maghera and Livourne.
On June 15, 1940, second-lieutenant Pierre Le Gloan (GC 3/6) shot down 5 Italian aircrafts (4 Fiat CR.42 and 1 BR.20) in 40 minutes with his Dewoitine D-520 over Saint-Raphaël. Le Gloan was in formation with captain Assolant when they saw 12 Fiat CR.42. Le Gloan destroyed 2 CR.42 and Assoulant returned to base with his guns jammed. Alone, Le Gloan continued his patrol. Over Hyères Le Gloan attacked 3 CR.42 and destroyed one plane, he broke the combat when 8 other Italian aircrafts arrived. The airbase at Luc called him back because it was attacked by Italian planes. Le Gloan destroyed his fourth CR.42 and one BR.20 from the 172nd strategic reconnaissance Squadriglia.
French OoB :
On June 10, 1940, Italy declared war, sounded like a backstab.
My previous troop numbers were wrong indeed.
The French Army in the Alps was composed of 175,000 men, but this army was at the same time attacked by Italian and German forces (General's Hoeppner XVIe panzer Korps with about 60,000 men). The Italians had 2 armies with a total of 22 divisions among them 4 alpine divisions (for a total of 312,000 men and 3000 guns according to what I could find) and the Germans had the 3. PzD as well as infantry divisions (like the motorized 13.ID) coming from the north from the Dijon and Lyon and heading for Grenoble, Chambéry and Voreppe that they will never reach due to the French stiff defense in the valleys and the accuracy of the French artillery.
The French had only 6 divisions among them 3 were fortress units + 65 artillery groups and 86 SES (Section d'éclaireurs-skieurs = ski recon platoons, elite troops). This army had not only to fight on the borders but it was dispersed in the whole Savoie, Dauphiné and Alpes-Maritimes areas and it also had to stop the Germans in the Rhône and Isère valleys. General Olry formed a combat group (groupement Cartier) of 30,000 men with tanks and artillery and sent them in the Rhône-Isère area to meet the German forces.
In the Maurienne area :
The advanced French posts covering Modane, held by 9 battalions a few guns and SES, defeated the assaults of 3 Italian divisions. All the attacks are stopped by the Turra fort, close to the Mont Cenis, defended by second-lieutenant Prudhon and his 50 men. Despite heavy artillery preparation and the reinforcement of two other divisions, the fort did not fell into enemy hands and the Italians suffered heavy losses. The French alpine troops left the fort only on July 1, 1940 on orders after having held out for ten days. They received the honors of war.
In the Briançonnais area :
All the Italian attacks on Montgenèvre (17th-22nd June) failed despite 3 vs 1 numeric superiority mainly because of the French artillery.
In the Queyras valley :
The fightings took place in an uncommon cold with rain and snow storms. Heavy combats for the town of Abriès between 12,500 Italians and 7,500 French soldiers. French aspirant Gueury with five men took 52 Italian POWs : 3 officers and 49 Alpini.
In the Ubaye valley :
This valley controls the access to the Durance and to Barcelonnette. The Italian divisions are blocked by 3 French battalions and 5 SES.
Along the coast towards Nice :
The 15e Army Corps of general Montagne has faced 10 divisions and important artillery support for 10 days. On June 18, the Italians tried without succes to take Menton and then on June 21, at dawn, the Italian divisions massed in the area launched attacks on the French positions. The attack on Nice failed and despite heavy fights the forts at Pierre-Pointue and Cap-Martin (around Menton) didn't fall. The Port-Saint-Louis fort in this area, without radio liaison, continued to fight after the armistice and finally the garisson left its position to join the French troops. They closed the fort and took the keys.
On June 24, 1940, the French positions are still intact on both northern and eastern flanks in the Alps.
At 9 PM order received to cease hostilities on all fronts, effective 12:35 AM French Summer Time.
At 10 PM, General Olry stated that:
"Of the thirty-two divisions in the Italian army, nineteen were wholly or partly engaged against the outposts - and in a few cases the main elements - of our six divisions.
"We were outnumbered seven to one in Tarentaise, four to one in Maurienne, three to one in Brianconnais, twelve to one in Queyras, nine to one in Ubaye, six to one in Tinee, seven to one in L'Aution and Sospel, and four to one in Menton.
"Our adversary only made contact with, or approached, our main positions in Tarentaise and near Menton. All our fortified advance posts held out, even when encircled..."
On June 25, 1940,
At 12:35, bugles sounded the cease-fire all along the front. The Franco-Italian armistice came into effect (only due to pressure from Germany).
On the front against the German troops :
The 3.PzD and mot. 13.ID movements were hindered by the destruction of several bridges and faced the groupement Cartier. The 13.ID took Aix-les-Bains but never reached Chambéry. Near Annonay and Sarras the 1st Spahis brigade (4th and 6th Spahis regiments) blocked the German advance.
The 3.PzD had the task to take Grenoble and encountered roadblocks at Voreppe defended by the engineers of colonel Brillat-Savarin, the marine infantry from capitaine de frégate Protche and supported by heavy artillery positionned in the mountains (104th RALT towed heavy artillery regiment). 3 attacks from the Panzers failed because of the artillery fire well directed by the forward observer captain Lambert on the Bec de l'Echaillon. On June 24, a new strong German attack is stopped by the French artillery which fires on the German tanks, motorized columns and troops. In the town of Echelles held by 2 French companies and 2 artillery batteries the Germans lost 400 men without result. Voreppe remained uncaptured like Grenoble when the cease-fire occured. The Germans had lost more than 1000 men.
Finally France had lost the city of Menton plus 600 km2 all along the border. Beside all the Italian losses, the French troops captured also 500 Italian soldiers.