From an earlier answer of mine

There is a seeming paradox concerning Vichy and the fate of France's Jewish population during the occupation. On one hand, the survival rate of Jews in France was far higher than that of the Low Countries. Only a quarter of the Jews in France were deported, compared approximately 78% of the Netherlands and 45% of Belgium's Jews. These lower numbers were known at the time and Vichy officialdom seldom met the German quotas for deportation, much to the consternation of the SS and other German officials. Conversely, Vichy was far more proactive in its antisemitic measures than arguably any other German ally or occupied power on the continent. Vichy's justice ministry enacted laws restricting Jewish professional life and citizenship and the Vichy press gave free reign to all sorts of antisemitic invective. Many of the leading intellectual and political lights of Vichy were highly antisemitic and such attitudes seeing Jews as alien and un-French predated 1940 and continued into the postwar period. Additionally, of the 25% of French Jews deported, the Vichy police and other French state officials did the majority of the work. Yet, a closer examination of both Vichy and the occupation reveals that this particular paradox is not so mysterious. The relatively high survival rate of Jews in France, both French- and foreign-born, had more to do with a unique constellation of factors ranging from timing, occupation boundaries, and social factors.

France was unique among the Third Reich's victims in that it was the sole great power to surrender to German occupation. This immediately set German occupation policies apart from other examples like Belgium or the Netherlands. In those two latter examples, the largely urban and geographically smaller countries were more suited to a more hands-on occupation. Belgium, for example, came under direct military government while the Netherlands became the site of a turf wars between the Reichskommisar Seyss-Inquart, local Dutch fascists, the SS, and the bvarious military commands. In both of these cases, as in Denmark and Norway, the native civil service remained roughly intact an there was a small political group of native collaborators willing to be up-jumped into limited political power. But here, Germans remained in executive control, even if such control was characterized by the polycratic infighting typical of the Third Reich's governance.

France was different. Under Petain, the French possessed a modicum of control both over the state and France's colonies. This relative independence was a byproduct of the confused German response to their total victory in 1940. In short, Germany suffered from a wealth of plans to deal with France in the aftermath of Fall Gelb. Some conceived of a fascist France aiding German hegemony, while still other Germans envisioned a partition of France into Aryan sub-states like a Norman state. Between these two poles was a more extemporizing consensus that sought to make occupation policy suit immediate needs of the war effort and German state policy. This middle position, which was far from coherent, meant that there needed to be some form of French executive. Additionally, the size of France and the limits of German manpower meant that there needed to be some native leadership to make the occupation run smoothly.

What this meant for Vichy's Jewish policy was that France was to an extent a master of its domain, even if the threat of German intervention hung like a cloud over Vichy policymaking. The results did not speak well for Vichy's moral standing. The motley of rightists in Vichy such as Action Française's ideologues constructed a civic order that redrew French citizenship to exclude Jews and the overall tone of Vichy policies considered Jews to be a foreign body inside France. Foreign-born Jews like the novelist Irène Némirovsky were the early target of French ire as stateless Jews, and were thus over-represented among the 25% of Jews deported from France. This was of a piece with the Low Countries, which had a higher-concentration of non-indigenous Jews such as Anne Frank's family, who emigrated to the Netherlands in the mid-1930s. Yet French control over the Jewish citizenship meant there was an extra layer of bureaucracy for the Germans to contend with when they began in 1942. Other areas of occupied Europe presented less bureaucratic friction, so it was not surprising that the Germans tried there first before dipping into rendering France Jew-free.

The size of France also meant that it was much harder for both Vichy and the Germans to get a complete handle on the Jewish question in France. As seen in this map, the occupation was a mess of multiple zones and restrictions ranging from the Zone libre of southern France, which was not under direct German occupation to Alsace-Lorraine, which were new Reichsgaue. This created different jurisdictions and accentuated the rivalries that were inherent to Nazi rule. The jurisdiction that was to be the savior for many Jews in France was not Zone libre, but rather the Italian occupation zone in Provence and Savoy. Although Vichy did much to restrict Jewish movement and resources, it was possible to move to a safer zone. Jews in smaller geographic entities like Belgium did not have this option.

The comparatively late timing of French deportations, ca. 1942, also encouraged a number of Jews to flee to safer areas. Although actual knowledge of genocide was far from concrete, there was a general sense that bad things were happening in the East and that it would be best for Jews to avoid this fate. The dissolution of the Italian zone after September 1943 removed the last real sanctuary for Jews in France, but it also gave them time to prepare either by going into hiding or forging papers.

The response of Vichy to Jews disappearing was far from sanguine. Vichy officialdom and various French institutions like the Catholic Church were either hostile or indifferent to the fate of the Jews, but the opening waves of deportations did arouse some resistance among gentile French. This was the excuse many Vichy officials gave to the Germans when deportations fell short. There was an element of truth to these explanations. Try as it might to turn back the clock to a pre-1789 conception of Frenchness, Vichy could not break the concepts of civil society that had characterized much of the Third Republic. French Jews were highly assimilated into French society and although antisemitism was quite strong in many French quarters, French Jews had social connections and capital which aided them in this period. Although French civil society was anemic and suffered from the twin burdens of Vichy and the material dearth of occupation, it still existed. Moreover, by mid-1942 and especially by 1943, there was one salient fact that many Europeans began to appreciate: Germany was going to lose the war. Around this period, for example, members of the Polish Home Army began issuing declarations that its was in Poles' interests as good Catholics to shelter Jews. This did not necessary mean that waning German fortunes stoked the embers of philosemitism; many Polish leaflets calling for sheltering the Jews also stressed they were a foreign entity that had exploited Poles in the past and would need to find a new home after the Germans had been thrown out. A good many Europeans recognized that saving someone from German aggression was an insurance policy for the postwar period when someone might go poking around in their more than questionable actions during the period of German hegemony. Such actions seldom translated into a mass numbers of Jews being saved from deportation, but rather loosened the net somewhat for the Vichy officials responsible for the Aktions.

It also needs to be stressed that many Jews themselves took their survival into their own hands. The size and geographic variety of France, especially in the rugged south, lent itself well to disappearing. The relative lateness of the deportation also meant that many Jews found themselves into resistance bands. The French resistance, which had only really started to grow with Barbarossa when French Communists started fighting en masse, was accommodating to some Jews fleeing the deportations, especially the adolescents and other youth. Like other elements of the French polity, the resistance (which was also incredibly heterogeneous) was not philosemetic, but secular traditions in French civic society and the assimilation of French Jews meant that Jews were not an automatic other in resistance circles as they were in Eastern and Central Europe. The upsurge in resistance by 1942 thus dovetailed with the deportations.