On arrival, he found difficulties occasioned by the ascendancy which Jansenism had taken under his predecessor, "he thought himself obliged to forbid and even to expel" some difficult priests.

He knew all the ecclesiastics of his diocese, received them with benevolence, was always ready to listen to them, and to enter with them in the minutest details on what concerned the good of the parishes, the salvation of souls, and the relief to be carried where it was needed.

– Michaud, Ancient and Modern World Biography, 1843, 2nd EditionIn 1776, in the middle of the night, a town distant from Châlons of twelve or fourteen leagues broke out in flames.

Holding true to his belief in modesty, the Bishop yielded only to the encouragement and repeated orders of the King, who saw in his choice the interest of religion.

De Juigne carried in his new diocese the same spirit, the same principles according to which he had governed that of Châlons, "the same prudence, the same moderation, the same gentleness, the same attention to maintain the peace, to try to maintain it between the priesthood and the magistracy; even zeal for ecclesiastical discipline and sound doctrine; even munificence towards the poor, his immense income was employed in alms, in good works, in pious institutions."

The prelate made up for this by selling his dishes, by committing his patrimony, and by taking large loans, for the guarantee of which the Marquis de Juigné, his elder brother, was forced to pay the sum of a hundred-thousand crowns.

May the Gospel be proclaimed, may divine worship be celebrated with decency and dignity, may the churches be provided with virtuous and zealous priests; that the poor of the people are helped, this is the destination of our tithes, that is the end of our ministry and our vows.

He helped them first with his purse, the sale of the few precious effects which remained to him, even of his chapel, then of the gifts which he had received from Catherine II of Russia and of princes and great prelates of Germany.

He even found means of establishing a seminary in Konstanz, where young clerics were formed to replace the priests decimated by the revolutionary fury.

He returned to Paris in 1802, after the promulgation of the Concordat, and without difficulty resigned, at the hands of Pope Pius VII who asked for it, his archdiocese on 31 January 1802.

Juigné then lived in retirement among his family, beloved by his old diocesans, limiting his pleasures to solitary walks, where he was astonished to be welcomed by a crowd of silent homages addressed much to his dignity, on which he bore no discernible mark.

He visited with an inimitable simplicity his successor at Paris, Jean-Baptiste de Belloy, in the palace formerly his own, where both exercised respect and maintained the best relations.