He was made a cardinal in the consistory of 19 December 1539, by
Pope Paul III. The King (and no doubt
Mme. d'Estampes) had been extremely annoyed when Sanguin had not been named a cardinal in the Consistory of 20 December 1538, as they had expected. He was assigned the Deaconry of
Santa Maria in Portico on 15 July 1541, which was temporarily (
pro hac vice) promoted to the rank of
titular church. His red hat was sent to him in France, and was presented to him by the Papal Legate,
Cardinal Alessandro Farnese in a ceremony held in Notre Dame de Paris on Pentecost, 1540. Sanguin first presented himself in Rome for his introduction into the Roman Curia on 20 December 1547, and was received by the Pope on 22 December. He was presented with his ring on 9 January 1548 and granted the right to speak in Consistory. He was named
Grand Aumonier of France on 7 August 1543, in succession to Cardinal
Jean Le Veneur, who had died on the same day. In 1544 Cardinal Sanguin's niece's brother, Charles Pisseleu, who had been Administrator of the diocese of Mende since 1538, was made Bishop of Condom, thanks to the patronage of King Francis' sister, Marguerite of Navarre. The appointment was approved by Pope Paul III on 15 June 1545. In 1546 Bishop Charles' half-brother, François Pisseleu, a nephew of the Cardinal, was named Bishop of Amiens (He resigned in 1552). Cardinal Sanguin was made Lieutenant-General of Paris in 1544, the post his brother had held, to defend the city against the threats of
Charles V, Holy Roman Emperor, in which capacity he was among the delegates charged with negotiating the peace with the Emperor. He served as hostage, guaranteeing the peace which was concluded. ==In disfavor==