Bonnet supported the Vichy government and served on the National Council from December 1940, but the council never met, and his role in Vichy was small. Bonnet spent most of World War II living on his estate in the Dordogne and attempting to secure himself an office in Vichy, though Bonnet was later to claim to have been involved in the Resistance. According to Gestapo records, Bonnet contacted the Germans once in February 1941 to see if it were possible if the Germans would pressure Laval to include him in the Cabinet and again in June 1943 to reassure them that he had no intention of leaving France to join the Allies. In November 1942, Bonnet agreed, albeit very reluctantly to testify for the prosecution at the planned trial of Herschel Grynszpan. Bonnet was to testify that his efforts at reaching a rapprochement with the "Reich" had been sabotaged by the Jews, who were intent on starting a war with Germany, and that Grynszpan had assassinated Ernst von Rath as part of an alleged Jewish conspiracy to push France into war with Germany. However, the trial was never held as Gryszpan's planned defense that he was having a homosexual relationship with Rath, and had shot him as part of a lover's quarrel meant from the German viewpoint the trial was too risky as people might have believed that claim.