After a comment by a kind reader, I have tried to search a little about Georges Simenon’s stance during the Second World War.
So far as the facts are concerned, I’ve been able to extract the following information: (Source: Chronology by Jean-Baptiste Baronian)
1940. Georges Simenon is named high commissioner for the Belgian refugees of the department of Charente-Inférieure. His mission completed at the end of four months, he first settles in the forest of Mervent, then at Fontenay-Le-Comte, in the Vendée, where a physician diagnoses an illness that would leave him but two or three years to live. With that, he immediately begins writing Je me souviens… [I Remember], the first of his autobiographical works, in a sentimental manner intended for his son.
1942. He gets settled in Saint-Mesmin-le-Vieux, still in the Vendée, and publishes La Veuve Couderc (Ticket of Leave) and Maigret revient (Maigret Returns), a collection of stories (Cécile est morte – Les Caves du Majestic – La Maison du juge) marking, as the title indicates, the return of Maigret to the bookstores.
1945. After have been restricted to “permanent residence” at Sables-d’Olonne, Simenon comes to live in Paris for several months to prepare for his departure for the United States, which had recently caught his interest. In October, he disembarks at New York with Tigy and Marc.
Simenon lived in the Vendée during the Second World War. Simenon’s conduct during the war is a matter of considerable controversy, with some scholars inclined to view him as having been a collaborator with the Germans while others disagree, viewing Simenon as having been an apolitical man who was essentially an opportunist but by no means a collaborator. Further confusion stems from the fact that he was denounced as a collaborator by local farmers while at the same time the Gestapo suspected him of being Jewish, apparently conflating the names “Simenon” and “Simon”. In any case, Simenon was under investigation at the end of the war because he had negotiated film rights of his books with German studios during the occupation and in 1950 was sentenced to a five-year period during which he was forbidden to publish any new work. This sentence, however, was kept from the public and had little practical effect.
The war years did see Simenon produce a number of important works, including Le Testament Donadieu, Le Voyageur de la Toussaintand Le Cercle des Mahé. He also conducted important correspondence, most notably with André Gide.
Also in the early 1940s, Simenon had a health scare when a local doctor misdiagnosed him with a serious heart condition (a reminder of his father), giving him only months to live.
Simenon escaped questioning in France and in 1945 arrived, along with Tigy and Marc, in North America.
And from The New Yorker:
In 1940, after the Second World War got under way, Simenon moved his family to a village in the Vendée, in west-central France. Because of travel restrictions, he got stuck there. In the morning he wrote; in the afternoon he played cards with the locals in a café. His war record was mixed. He ran a refugee center, very energetically, people say. On the other hand, four of the nine movies made of his books during the Occupation were produced by what he knew was a Nazi-run company. For that organization, he also signed a statement that he was an Aryan. Pierre Assouline says that Simenon was neither a collaborator nor a resister but just an opportunist. Alan Riding, in his recent, evenhanded book on the Occupation, “And the Show Went On,” also brushes Simenon’s case aside. But most people suffered severe privations during the war. Meanwhile, Simenon got richer (primarily from those movies). And so, once the Occupation ended, the purge committee of the French writers’ union began looking into his case. Simenon became truly frightened—some writers, on the committee’s recommendation, were barred from publishing—and in 1945, as soon as he could get out, he sailed with his family to North America. They eventually settled in the genteel town of Lakeville, Connecticut, where Simenon was restless but productive. (Many of his best books were published in his middle years, from about 1938 to 1951.) After a ten-year exile, the family returned to Europe, settling near Lausanne, Switzerland, which for Simenon, as for others, was a tax haven.
Regarding the presence of the Second World War in his oeuvre, it is evident, as far as I understand, that none of his Maigret books makes explicit reference to any historical event. They are considered timeless. But with respect to his his ‘romans durs’, at least two take place against the backdrop of the Second World War –Le Train,1958 (The Train) and Le Clan des Ostendais, 1947 (The Ostenders), while La Neige était sale, 1948 (Dirty Snow) and Les autres, 1962 (The Others) evoke the Second World War in a sense.