He was educated by his uncle Clément Bonzi, bishop of Béziers, who made him join the ecclesiastical state and he became Resident of Ferdinando II de' Medici, Grand Duke of Tuscany in the French court. Later he was appointed commendatory abbot of several abbeys in France.
Piere de Bonzi was elected bishop of Béziers on June 7, 1660, th 5th member of the family to become bishop of that see. Later he became French ambassador in different countries in Europe. On September 28, 1671 was promoted to the metropolitan see of Toulouse.
In 1672 Bonzi was created cardinal priest by Pope Clement X, and transferred to the metropolitan see of Narbonne two years later. He participated in the Papal conclaves of 1676, 1689 and 1691. He opted for the title of Sant'Onofrio on October 19, 1676. Then he was transferred to title of S. Pietro in Vincoli and later opted for the title of Sant'Eusebio. Since 1693, approximately, he suffered from epilepsy and because of poor health he did not participate in the Papal conclave of 1700.