Having started writing in 1938, his poems appeared, under the pseudonym "Benjamin Phelisse", in the clandestine publications of the Resistance directed by Paul Éluard, notably L'Honneur des poètes [fr], and he was an active contributor to Jean Lescure's magazine Messages.
His collections have subsequently been published regularly by Gallimard, along with interviews with Bernard Pingaud on his poetry and poetic creation in general.
Frénaud forged lasting friendships with painters Raoul Ubac and Jean Bazaine, whose exhibitions he accompanied with his prefaces.
The couple acquired and restored an old house in Bussy-le-Grand, Côte-d'Or, and set up a workshop where Monique Mathieu bound many of her husband's works, as well as those of their literary and painter friends.
[3] In 1999, Monique Mathieu donated ninety-five works (twenty paintings, fifty-eight drawings and collaged papers, fourteen engravings and three sculptures) to the town of Autun (Saône-et-Loire).