Jean was elected bishop of Avranches on 20 September 1327 and made his profession to the Holy See on 17 May 1328. Following the French victory at the battle of Cassel on 23 August 1328, which ended the peasant revolt in Flanders, Jean was charged with securing conditions of peace. Philip VI empowered him to demolish the fortifications of Ypres, Courtrai and certain other cities, and to lift the sentence of excommunication imposed on the citizens of Bruges.
