[2] He was a graduate of the Marie-Louise class (1911–1913) and Montmirail promotion, becoming an infantry officer of la Coloniale in WWI, distinguishing himself in the Champagne offensive.
[3] In the mid-1930s, he created - with captain Jean Chrétien - a clandestine army network to react to any communist coup attempt, which gained support from André Brouillard, head of the Deuxième Bureau (former secret service) in Paris.
They were summoned to the newly requisitioned Hôtel de Crillon by Nazi general Bogislav von Studnitz, who said Groussard should be shot for burning fuel depots after he complained about not being allowed to rejoin army comrades who'd moved south of Paris.
One, Gabriel Jeantet, in charge of propaganda for Vichy, put him in contact with another, industrialist Paul Dungler, who created the 7e colonne network in Alsace which collected intelligence on the Nazis.
Huntziger, however, asked him to continue to work against the Nazis as a "sniper"; he authorised Groussard's request to visit Free French leader Charles de Gaulle in London on a mission named Gilbert.
[11] Labat ran it secretly from his home before it was recast with an avowable title as an 'anti-masonic intelligence service'; he sent information to Vichy with a broad scope, covering the activities of freemasons, gaullistes, Nazis and communists.
[2] Groussard also acted in his Vichy roles in an 'official' manner: he refused a patriotic request from the Marseille-based and openly vichysto-résistant general Gabriel Cochet, instead giving local CIE director Joseph Darnand a search order regarding Cochet and trying to infiltrate his group[12](Cochet was interned by admiral François Darlan in June 1941); Méténier wrote to the Nazi leader in Paris, Helmut Knocken, to explain the CIE's shared goals in extending their operations into the zone occupée, specifically to root out communists in the Resistance;[13] Antoine Marchi, former cagoulard and a member of a groupe de protection, was arrested on the instruction of police commissioner Charles Chenevier as he appeared to be behind of the assassination of Marx Dormoy, the former Front Populaire minister who had tried to suppress La Cagoule.
On his return to France, Groussard was arrested on the instructions of general Darlan,[18] joining former prime minister Paul Reynaud, his fellow politicians Georges Mandel and Jean-Louis Tixier-Vignancour and aircraft manufacturer Marcel Dassault as a detainee in Vals-les-Bains.
After a final release, he returned to Cannes before evading another arrest attempt[19] and escaping to Switzerland in November 1942 in a market gardener's cart during the invasion of the zone occupée by the Wehrmacht and Italian forces.
[21] In Geneva, he met French lieutenant (and future general) André Devigny and British vice-consul Victor Farell, the latter promising financial support.
With the help of Swiss intelligence officer captain Pierre Clément as their technical advisor, they quickly cast the net of the Gilbert networks, named after Groussard's abortive mission to London, across France, Germany and Italy.
After Véra's death in July 1971, Groussard married his former partner and secretary, Suzanne Kohn (sister of Antoinette Sasse and former collaborator of Jean Moulin) in December 1971.