In 1671, de Bryas was named bishop of Saint-Omer in succession to Ladislas Jonart, who had just been translated to Cambrai. He took possession of the see by procuration on 11 April 1672 and made his solemn entry into the see on 11 June 1672. At Jonart's death, de Bryas again succeeded him, now as archbishop of Cambrai, where he was installed on 28 October 1675. Eighteen months later, Louis XIV of France took control of the city at the conclusion of the Siege of Cambrai, and by the Treaties of Nijmegen the Habsburgs ceded the duchy of Cambrai to French control. A report to the new king described the archbishop as eating simply off pewter tableware, and spending his free time visiting the sick and prisoners.