In 1780, Barbé-Marbois sent a questionnaire to the governors of all thirteen former American colonies, seeking information about each state's geography, natural resources, history, and government.

[4] In 1795, he was elected to the Council of Ancients, where the general moderation of his attitude, especially in his opposition to the exclusion of nobles and the relations of émigrés from public life, brought him under suspicion of being a royalist, though he pronounced a eulogy on Napoleon Bonaparte for his success in Italy.

In return for these favours, he heaped praise upon Napoleon; yet, in 1814, he helped to draw up the act of abdication of the emperor, and declared to the Cour des Comptes, with reference to the invasion of France by the Sixth Coalition: In June of that year, under the First Restoration, Barbé-Marbois was made Peer of France by King Louis XVIII, and confirmed in his office as president of the Cour des Comptes.

Deprived of his positions by Napoleon during the Hundred Days, he was appointed Minister of Justice under the Duc de Richelieu (August 1815), tried unsuccessfully to gain the confidence of the Ultra-Royalists, and withdrew at the end of nine months (10 May 1816).

[5] In 1830, when the July Revolution brought Louis Philippe and the Orléans Monarchy, Barbé-Marbois went, as president of the Cour des Comptes, to compliment the new king, and was confirmed in his position.