Mobilized when the war broke out, he spent nearly a year in the army as a second class soldier: after the defeat, Edouard Gaumont briefly resumed his studies, and obtained a license in philosophy: then he enrolled at the end of 1940, as a lawyer at the Aix-en-Provence Court of Appeal.

[2] With the Liberation, Edouard Gaumont stops his legal activities to embrace the career of the weapons: pupil of the Military school of the Infantry and the tanks of combat, he is at his exit, in 1946, affected at his request in Guyana; his rise in the military hierarchy is rapid, since he was appointed in 1949 commander of the colonial infantry company of Guyana; there, while doing his job as a soldier, he gives lectures and private lessons, and volunteers to lead the cultural activities of the Félix-Eboué home in Cayenne.

[2] His political activity began in 1948: he was an unsuccessful candidate in January for the partial legislative elections in Guyana, with a view to filling the seat left vacant by the death of René Jadfard; this failure brought him back to his military career, and it was in 1950, when he took temporary leave of his department of origin, that he was promoted to the rank of colonial infantry captain.

During this last legislature of the Fourth Republic, Edouard Gaumont did not take part in the ballot during the investiture of Guy Mollet (January 31, 1956); he votes for special powers in Algeria (March 12, 1956) and against the ratification of the treaties establishing the European Economic Community and Euratom (July 9, 1957).

Edouard Gaumont, as a Member of Parliament, also stood out in his capacity as a politician for having participated in changing the situation of Guyana within the National Assembly, in particular on the laws of departmentalization (Social Security, etc.