From Dictionnaire Historique, ou Histoire Abrégée, by Abbé François-Xavier de Feller (Volume 10, Fifth Edition, pages 325-326, 1823):

PICHON (Thomas-Jean), doctor of theology and Canon of the Saint-Chapelle in Le Mans, was born in that town in 1731. He began his studies at the college attached to the Oratory in Le Mans and completed them at the college of that name in Paris. After ordination he joined the Bishop of Perpignan, Monsieur d’Havrincourt, and went to work for him in his Diocese. However, he remained there only two years before returning to Paris, where he wrote several books. He was then appointed Canon and Precentor at the Saint-Chapelle in Le Mans. The Bishop of Le Mans entrusted to him the general supervision of the convents in the diocese, while the brother of King Louis XV appointed him historiographer for his estate in Le Mans. At the Revolution he was deprived of his various livings and appointments. It is said that he was offered the Constitutional Diocese of Le Mans [set up by the commissaries to the Convention] and that he refused it, but he did accept the post of administrator of the general hospital there. He died on 18 November 1812. He wrote a considerable number of works:

1. La Raison triomphante des nouveautés, ou Essais sur les moeurs et l'incrédulité; Paris, 1758, 1 vol. in-12.
2. Traité historique et critique de la nature de Dieu, 1758, in-12.
3. Cartel aux philosophes à quatre pattes, ou l'Immatérialisme oppose au matérialisme, Bruxelles, 1763, in-8°.
4. La Physique de l’histoire, ou Considerations generales sur les principes élémentaires du temperament et du caractère naturel des peuples, la Haye, 1765, in-12.
5. Mémoire sur les abus du célibat dans l’ordre politique, Amsterdam, 1766, in-12. This work proved unpopular in Le Mans, where the Abbé was living, and he was reproached over several matters.
6. Mémoire sur les abus dans les mariages, Amsterdam, 1766, in-12.
7. Les Droits respectifs de l’état et de l’église, rappelés à leurs principes, Avignon, 1766, in-12.
8. Des Etudes théologiques, ou Recherches sur les abus qui s'opposent aux progrès de la théologie dans les écoles publiques, et sur les moyens possibles de les reformer en France, par un docteur manceau, Avignon et Paris, 1767, in-8°
9. Principes de la religion et de la morale, extraits des ouvrages de Saurin, ministre du saint évangile, 1768, 2 vol.in-12. A comment in the Dictionnaire des Anonymes, vol. 4, page 327, tells us that this book was actually written by Durand, a Calvinist minister in Lausanne, who published it in 1767 under the title ‘Esprit de Saurin’. Abbé Pichon drew heavily on this work, making certain additions and deletions, and then retitled it as above.
10. Sacre et couronnement de Louis XVI, précédé de recherches sur le sacre des rois de France, et suivi d'un journal historique de ce qui s'est passé à cette cérémonie, avec figures gravées par Patas, Paris, 1775, in-4°.
11. Les Argumens de la raison en faveur de la religion et du sacerdoce, 1776; Examen de l'Homme d'Hélvetius, same year. While duly acknowledging the zeal of Abbé Pichon and his capacity for hard work, we regret that in this work he allows his imagination to run away with him and that he has tried to defend certain paradoxes which do not do justice to his powers of judgement.