Some articles which Fauriel published in the Decade philosophique (1800) on a work of Madame de Staël's--De la littérature considerée dans ses rapports avec les institutions sociales--led to an intimate friendship with her. About 1802 he began a liaison with Madame de Condorcet which lasted till her death (1822). It was said that he gave up all his energies to love, friendship and learning. The salon of Mme de Condorcet was a rallying point for the dissentient republicans. Fauriel was introduced by Madame de Staël to the literary circle of Auteuil, which gathered round Destutt de Tracy. Those who enjoyed his closest intimacy were the physiologist Cabanis (Madame de Condorcet's brother-in-law), the poet Alessandro Manzoni, the publicist Benjamin Constant, and François Guizot. Later Tracy introduced to him Augustin Thierry (1821) and perhaps Adolphe Thiers and François Mignet.
During his connection with Auteuil, Fauriel's attention turned to philosophy, and he began work on a history of Stoicism, which was never completed, all the papers connected with it having accidentally perished in 1814. He also studied Arabic, Sanskrit and the old South French dialects. He published in 1810 a translation of the Parthenais of the Danish poet Baggesen, with a preface on the various kinds of poetry; in 1823 translations of two tragedies of Manzoni, with a preface "Sur la théorie de l'art dramatique"; and in 1824-1825 his translation of the popular songs of modern Greece, with a "Discours préliminaire" on popular poetry.
The revolution of July, which put his friends in power, opened to him the career of higher education. In 1830 he became professor of foreign literature at the Sorbonne. The Histoire de la Gaule méridionale sous la domination des conquerants germains (4 vols., 1836) was the only completed section of a general history of southern France which he had projected. In 1836 he was elected a member of the Academy of Inscriptions, and in 1837 he published (with an introduction the conclusions of which would not now all be endorsed) a translation of a Provençal poem on the Albigensian war. After his death his friend Mary Clarke (afterwards Madame J. Möhl) published his Histoire de la littérature provençale (3 vols., 1846)--his lectures for 1831-1832. Fauriel had a preconceived and somewhat fanciful theory that Provence was the cradle of the chansons de geste and even of the Round Table romances; but he gave a great stimulus to the scientific study of Old French and Provençal. Dante et les engines de la langue et de la littérature italiennes (2 vols.) was published in 1854.
Fauriel's Mémoires, found with Condorcet's papers, are in the Institute library. They were written at latest in 1804, and include some interesting fragments on the close of the consulate, Moreau, etc. Though anonymous, Lalanne, who published them (Les Derniers Jours du Consulat, 1886), proved them to be in the same handwriting as a letter of Fauriel's in 1803.