His works are numerous: "Les Fées au Moyen âge" and "Histoire des légendes pieuses au Moyen âge"; two books filled with ingenious ideas, which were published in 1843, and reprinted after the death of the author, with numerous additions under the title "Croyances et légendes du Moyen âge" (1896); "Histoire des grands forts de la Gaule et de l'ancienne France" (1850, a 3rd ed. revised, appeared in 1867 under the title "Les Forts de la Gaule et de l'ancienne France"); "La Terre et l'homme", a general historical sketch of geology, geography and ethnology, being the introduction to the "Histoire universelle", by Victor Duruy (1854); "Histoire des religions de la Grèce antique", (3 vols., 1857–1859); "La Magie et l'astrologie dans l'antiquité et dans le Moyen âge" (1863); "Histoire de l'ancienne Académie des sciences" (1864); "Histoire de l'Académie des Inscriptions et Belles Lettres" (1865); a learned paper on the reports of French archaeology, written on the occasion of the Exposition Universelle (1867); a number of articles in the "Encyclopédie moderne" (1846–1851), in Michaud's "Géographie universelle" (1858 and seq.), in the "Journal des savants" in the "Revue des deux mondes" (1873, 1877, 1879–1880, &amp;c). A detailed bibliography of his works has been placed by Auguste Longnon at the beginning of the volume "Les Croyances et légendes du Moyen âge".