International audienceThis study on Beethoven in France, written for his 250th anniversary, explores the intellectual journey of Brigitte and Jean Massin, the authors in 1955 of Ludwig van Beethoven, still today the French language standard biography. Thanks to unpublished documents of the Fonds Brigitte et Jean Massin at the Institut de Mémoire de l’Édition Contemporaine (IMEC), and other sources, the article retraces their collaboration, starting with their encounter in 1946 in the realm of the Catholic church, and their activism from 1953 on as members of the French Communist Party (PCF). Their notes and manuscripts inform the genetic history of their Beethoven book, originally designed for the music lover, and organized in three parts –...