[2] The Bishop of Bourges, Léon Potier de Gesvres, appointed him Vicar General of the diocese and Archdeacon, Canon, and Prebendary of his cathedral.

[4] Belloy participated as a delegate from the ecclesiastical Province of Embrun in the famous Assembly of the French Clergy of 1755,[5] which began on 25 May and concluded on 4 November.

Louis XV now proposed to turn the free grant into an annual tax of 5%, and to make that possible, he demanded a general survey of the value of all ecclesiastical benefices in France.

[6] Belloy took sides with the moderate party (Feuillants), led by Cardinal Frédéric-Jérôme de la Rochefoucauld, the President of the Assemblée du Clergé, and contributed to the restoration of tranquility in the Church of France.

Belloy was transferred to Marseille by Pope Benedict XIV on 4 August 1755;[7] he gained the confidence of both parties, as well as the competing factions of Jesuits and Dominicans, and restored peace.

He celebrated Mass for the last time in the Cathedral on 31 August 1790, and then retired to Chambly, a little town near his birthplace, where he remained during the most critical period of the Revolution.

[14] At the specific request of Napoleon I, Belloy was promoted to the rank of cardinal of the Holy Roman Church by Pope Pius VII in the consistory of 17 January 1803.

Pius VII personally placed the cardinal's galero on his head at a consistory held in the Grand Salon of the Archbishop's Palace in Paris on 1 February 1805.

On 2 October 1803, Belloy have been named a Member of the Legion of Honor, then Grand-Officer (1804), and then Grand-Eagle (1805)[15] He restored the Crown of Thorns (10 August 1806) to its place of honour in the Sainte Chapelle.

On 27 January 1807 the cardinal issued an order, fixing the number of canons at Notre Dame at nineteen members, including the three vicars general.

[17] Belloy was buried on 25 June in the Chapelle Saint-Marcel in Notre Dame, where the monument erected by Napoleon in his honour, the work of Pierre Deseine, is one of the finest in the cathedral.