Although in this new sphere Camus laboured with the utmost devotion and untiring energy, living a life of ascetic severity, fasting, sleeping on straw, or spending whole nights in prayer, while his days were given to preaching, confirming, hearing confessions, visiting the sick, consoling the afflicted, advising, exhorting, patiently listening to the crowds who flocked to consult him, yet he still felt certain that the voice of God called him to solitude and to a perpetual retreat.
Desiring to spend the rest of his days among the poor whom he loved so well, he came to Paris, and took up his abode in the Hospital for Incurables, situated in the Rue de Sèvres. He reserved for himself out of his patrimony and benefices only 500 livres, which he paid to the hospital for his board and lodging, distributing the remainder among the needy.
In this hospital he passed his time in ministering to the sick, dressing their wounds, consoling, and instructing them, and performing for them all the functions of an ordinary Chaplain.
Even if he went out to visit friends in the vicinity of Paris, he never returned later than five o'clock in the evening. Occasionally he preached in the chapel of the Duke of Orleans before His Royal Highness, and at such times denounced vehemently the luxury and indolence of Princes and courtiers.
There was at this time a diocese in a no less pitiable condition than was Belley when Mgr. Camus was, at the King's desire, placed in charge of it. This diocese was that of Arras, and on the 28th of May, 1650, he was appointed by Louis XIV., acting under the advice of the Queen-Regent, to administer all the affairs of the diocese until such time as a new Bishop should be nominated to the vacant See by His Majesty and our Holy Father the Pope. Into this laborious task of sowing, ploughing, cultivating a vast weed-grown, and unpromising field, Camus threw himself with all his old ardour and energy. He did so much in a very short time that his name will long be remembered among the descendants of those from whom the troubles of the times snatched him so suddenly, but not before he had bound them to France while leading them to God by bands of love stronger than citadels or garrisons.