Here it is what I found in my researches:
In 1940, Italy on 10 June declared war against Britain and France and on 21 June Italian forces entered South Eastern France. It was quickly occupied Mentone on the coast, but on the mountains it was more difficult the conquests for the Italian troops. However on the 24th of June France and Italy signed an armistice effective the following day and allowing the Italians to retain the gains of several small communes as well as Menton. Additionally, a demilitarized strip 50 km wide from the French side of Mediterranean Sea to the Swiss border was agreed to be under the control of a specially established Italian-French Armistice Commission under the supervision of German and Italian officers.
In summer 1940, the Italian Armistice Commission ("Commissione Italiana d'Armistizio con la Francia", CIAF) produced two detailed plans concerning the future of the occupied French territories, according to historian Davide Rodogno:
Plan 'A' presented an Italian military occupation all the way to the river Rhone, in which France would maintain its territorial integrity except for Corsica and Nizza.
Plan 'B', proposed by senator Francesco Salata, the director of a section of the ISPI dedicated to Italian territorial claims, encompassed the Italian annexation of the Alpes Maritimes (including the Principality of Monaco) and parts of Alpes-de-Haute-Provence, Hautes Alpes and Savoie. The territory would be administered as the new Italian province of "Alpi Occidentali" with the town of Briançon (Italian: Brianzone) acting as the provincial capital (please read: https://archive.org/details/fascismseuropean0000rodo/page/90/mode/2up).
In addition to Nice and Corsica, the Italians planned further territorial claims to impose on defeated France. The problem of Italy's western border was raised as early as August 1940 with a limit that reached the Varo river, but included Antibes and substantial adjustments to the Alpine border up to Mont Blanc. A second project - that of Senator Francesco Salata, director of a special ISPI series dedicated to Italian claims - added direct dominion over the Principality of Monaco. On 19 October 1940, in a letter to Hitler, Mussolini stated that the time had come to establish the metropolitan and colonial borders of tomorrow's France, reducing it to proportions that would prevent it from starting to dream of expansion and hegemony again. The 850,000 Italians who formed the largest mass of foreigners in France, said the Duce, would be repatriated for a total of at least 500,000 in a year.
The Italian and German territorial acquisitions would have removed another four million inhabitants from France. The peace treaty would have reduced France to a state with 34-35 million inhabitants, with a tendency to decline further. As for acquisitions of a metropolitan and colonial nature, he added: "They are limited to Nice, Corsica and Tunisia. I don't count french Somalia because it is a classic desert". Among the numerous plans for the dismemberment of metropolitan France, one of the most complete and detailed was drawn up in 1942 by the Italian Armistice Commission with France (CIAF). It proposed a Plan A and a Plan B which were developed starting from the assumption that the military occupation would in any case remain a transitory phase awaiting victory.
Plan A, or «maximum project for the occupation of mainland France up to the Rhône and Corsica», was also called the «general governorship». He envisaged a regime of military occupation, with unimpaired sovereign rights, except for Nice and Corsica, where the Italians would settle "firmly in the corners of civil organisation". French legislation would have remained in force, but all provisions contrary to Italian interests would have been suspended. Extraordinary legislation would be carried out through the proclamations of a supreme commander or governor, while the French civil authorities and officials would continue to exercise their functions, unless replaced by political, military or public order needs. The prefects, their heads of cabinet and the sub-prefects would have been exempted, while the subordinate officials and administrators of the municipalities, departments and other minor local authorities would have remained in service. The administrative structure would have been composed of a governor general, a superintendent for civil affairs, eleven provincial governors, assisted by civil commissioners and extraordinary commissioners and, finally, a high commissioner for the principality of Monaco.
Plan B, in the event of implementation of the Plan B, the superintendents for Civil Affairs would have introduced the Italian legal system and provided the administration cadres of the new province of the Western Alps: prefecture, sub-prefecture and provincial offices (Civil Engineering, Finance, Post Office, Instruction). In Corsica, a general would have immediately replaced the French prefects and vice-prefects with civil commissioners to be installed in Bastia, Corte, Sartene. Other commissioners would be appointed in Grasse, Barcelonnette and in the two districts of Bourg-Saint-Maurice and Modane, thus ensuring the functioning of the dissolved local authorities. To make this plan operational, 326 officials would have been enough.
It is noteworthy to pinpoint that Rodogno wrote also about the possibility of creating another small italian province around Mentone and Nizza: the "Alpi Marittime", to be added to the Liguria region (while the "Alpi Occidentali" was going to be added to the Piemonte region).
Furthermore, Mussolini started a process of italianisation in the occupied areas since 1940, with opening of italian schools and prohibition to speak french officially (only italian was allowed).This process of italianisation was most successful in the city of Mentone, that had nearly 90% of italian speaking inhabitants in summer 1943. And was also opened again by the italian fascists a local newspaper/magazine (the "Nizzardo", closed by the French in the XIX century, when Nizza was given to France by the Savoya's "Regno di Sardegna"), that proved to be totally nationalistic -because it was in the editing hands of the local italian irredentists.
Finally, we must remember that the "french départements" occupied entirely in November 1942 southern France were: Alpes-Maritimes; Basses-Alpes; Hautes-Alpes; Isère; Savoie; Haute-Savoie; the Var; and Corsica; while those occupied partially were Ain; Bouches-du-Rhône; Drôme; and the Vaucluse.
The following are excerpts from the very detailed and interesting “The Italian Occupation of South-Eastern France, 1940-1943” written by Niall MacGalloway (https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/10858/NiallMacGallowayPhDThesis.pdf?sequence=2&isAllowed=y):
“The Italian Occupation of South-Eastern France, 1940-1943”, by Niall MacGalloway
The nature of the Italian zone of occupation makes it a difficult subject to examine. At different points during the war, the Italian zone of occupation encompassed different territories, making it difficult to talk about a single zone at any one time. Instead, the zone can be broadly divided into two temporal distinctions: those territories occupied from the signing of the Italo-French armistice in June 1940; and those territories which only came under occupation from November 1942.
The initial zone of occupation comprised of only 83,217 hectares and 28,473 inhabitants, the overwhelming majority of whom lived in the border town of Mentone. Mentone and the occupied communes in Savoie, Haute-Savoie and the Alpes-Maritimes remained the extent of the Italian zone of occupation until the Allied landings in North Africa prompted the Axis powers to occupy the remainder of unoccupied France in November 1942.
Prior to this invasion, Italy’s initial possessions had been treated as de facto annexed territories. The expansion of the zone of occupation brought a further eight départements under the control of Rome in their entirety, and another three were partially occupied. Nonetheless, even after the expansion of the zone of occupation, the territories initially occupied by Italy continued to be treated as annexed territories and were governed by different laws and by different agencies. As a result, it is possible to speak, if not of two separate Italian occupations, then of an Italian occupation with two distinct sections. Although governed by separate agencies, the two sections of the Italian zone of occupation existed simultaneously.
While the Italian annexed territories were subject to Italian law, this was never imposed on the occupied territories. Nonetheless, Italian organisations of law and order were present in these territories and Italian commanders did give orders to French administrative organs. In reality, of course, the Italian military presence in the region made it difficult for most mayors and public servants to ignore the wishes of the Italian military entirely. The Vichy government’s policy of collaboration with the occupiers in the hope that it would produce favourable results may also have created an atmosphere where such actions were acceptable. Unlike the annexed territories, however, any actions designed to co-operate with the Italian authorities were carried out thanks to the pragmatism of local government officials, rather than because they were legally obligated to do so: the legality of the Italian presence in the occupied territories had no real legal basis, especially in the armistice terms.
Despite her grandiose pre-war territorial ambitions, Italy opted for an initially small zone of occupation, most likely based upon pragmatism and economic and military realities. Italian troops were stationed inside the Linea verde (Green line), which roughly corresponded to the final position of the Italian troops.
Those territories stationed behind the Linea verde represented the extent of the initial zone of occupation, and the limits of Italy’s policies of annexation. French civilians were permitted travel within the limits of the Linea rossa (Red line). In practical terms, this covered almost the same area as the Linea verde, but encompassed small additional tracts of territory designed to compensate for mountain routes that were impassable in winter. The Linea viola (Purple line) represented an area fifty kilometres from the frontier which was to be completely demilitarised by the French army.
The armistice was also to be rolled out over a number of months, with demilitarisation of the Linea viola given the highest priority. In addition to these zones, a final Linea azzurra (Blue line) stretched far beyond the limits of the zone of occupation which gave Italian authorities the power to inspect French facilities as far afield as Lyon, Marseille and Toulon as well as Corsica.
Davide Rodogno has shown that by 1942, a time when Italy was practically starting to subordinate to Germany, two plans – Plan A and Plan B – had been established.
Plan A, also entitled “General Governorate”, foresaw a military occupation in which France would lose territorial sovereignty in the Nizzardo and Corsica, which would become Italian. French administrative staff would be dismissed, while 594 Italian officials, plus all Italian organisations, such as the carabinieri, would be sent to France.
Plan B envisaged an amalgamation of the Alpes-Maritimes and Monaco. Parts of the Alpes-deHaute-Provence, Haute-Alpes and Savoie would create the new province of Alpi Occidentali, containing 76,000 inhabitants with its capital at Briançon. This would become a full province of Italy, though difficulties were anticipated due to the sentiments of the population and communication issues. Corsica would be made autonomous, but dependent upon Italy.
Italy became increasingly aware that many of the territorial expansions that she made came at the behest of Germany. In France, the expansion of the zone of occupation to the Rhône was made possible only by the German diktat given to Pétain only hours earlier. Nonetheless, Italian subordination to Germany was once again demonstrated by the fact that Germany occupied the key cities of Avignon, Marseille, Lyon and Toulon (this city was inside the area under italian "control"!)>
Italy was determined to pursue her own policies in France. The most obvious example of this is the Italian policy towards Jews in the zone. In the years immediately following, scholars believed that the Jews were deliberately “saved” by the Italians. Italian anti-Semitism did not exhibit the same exterminatory drive that developed in Nazi Germany.
Davide Rodogno’s Plan A and Plan B for the future incorporation of French territories were certainly one way to "Italianise" areas of France, but it was not enough for Italy simply to declare the existence of new provinces. Plan B was arguably the more extensive of these two options and involved the amalgamation of the Alpes-Maritimes and the Principality of Monaco, which would presumably be re-styled as "Alpi Marittime". Tracts of the Alpes-deHaute-Provence, the Haute-Alpes and Savoie, would also be combined in order to create another new province: "Alpi Occidentali".
Despite the capital of this new province being placed at Briançon, it is likely that the region would gravitate towards Turin as the most dynamic city in the immediate vicinity. Although Nice was a growing urban centre, both Turin and Genoa were larger and benefitted from Italian policies designed to push these new provinces towards Piedmont and, to a lesser extent, Liguria.
Finally I want to pinpoint that at the outbreak of war, France was home to around 900,000 Italian citizens, but the real size of the Italian diaspora was far higher. There were also 500,000 Italians naturalised as French citizens during the 1930s, and many more who held dual French and Italian citizenship. In the department of Alpes-Maritimes, for instance, italian officials estimated that around 40% of the population of the department was Italian, and a further 40% of French citizens were of Italian descent. That means that 80% of the population in coastal areas like Mentone & near Nizza was clearly with italian roots directly or indirectly.
Because Italian nationality was passed down from the parent, regardless of place of birth, many people possessed dual French and Italian nationality. When war erupted, Italy began vigorously to assert its citizenship claims and consequently some men of the occupied areas served in the Italian Army.
And we must also remember that many thousands of Jews moved to the Italian zone of occupation to escape Nazi persecution in Vichy France. Nearly 80% of the remaining more than 300,000 French Jews took refuge there after November 1942, according to historians Paccini and Semelin. Indeed in January 1943 the Italians refused to cooperate with the Nazis in rounding up the Jews living in the occupied zone of France under their control and in March prevented the Nazis from deporting Jews in their zone.
In April 1943 German foreign minister Joachim Von Ribbentrop complained to Mussolini that "Italian military circles... lack a proper understanding of the Jewish question.". Quickly the italian marshall-general Cavallero answered saying that «The excessess against the Jews are not compatible with the honor of the Italian Army (Gli eccessi contro gli ebrei non sono compatibili con l'onore dell'esercito italiano.)»
Italian help to Jews after occupation of southeastern France in November 1942 (from https://www.holocaustrescue.org/chronology-of-rescue-by-italians):
Beginning in November of 1942, the Italian Army and Foreign Ministry officials occupy and administer eight French departments east of the Rhône River, in southern France. A French government remains in place, but the Italians control the area. In these Italian zones, French Jews and other refugees are protected right up until the Italians leave the war in September 1943.
Italian forces refuse to enforce any anti-Semitic measures in their zones. They refuse to allow any forced labor camps in their occupation zones. Further, the Italian occupying Army prevent any arrests or deportations of Jews in their area. As word spreads, thousands of Jewish refugees flee into the Italian zone. More than 50,000 Jews move to the Italian zone by July 1943. Twenty to thirty thousand of these are non-French Jews. Many of the Jews gravitate to the area around Nice (Italian "Nizza").
In order to prevent concentration of Jews in one area, refugees are sent inland to villages (like Saint-Martin-Vésubie) and even resort areas in each of the Italian occupied zones.
The Nazis strenuously protest these actions to Mussolini and representatives of the Italian Foreign Ministry. Mussolini's ministers and generals (like Cavallero) persuade him not to accede to the Nazi demands for deportations.
For nearly 10 months, Italian diplomats and the occupying military forces thwart the Nazis' "final solution" in southern France.
The following Italian diplomats were active in rescue of Jews in southern France: Gino Buti; Alberto Calisse, Consul in Nice; Guido Lospinoso, Interior Ministry Official and 'Inspector General of Racial Policy,' Nice; Vittoriano Manfredi, Consul in Grenoble; Augusto Spechel, Consul General in Nice; and Consul Vittorio Zoppi. In Paris, Consul General Gustavo Orlandini; and Vice Consuls Luciolli and Pasquinelli.
