By that time, he was a noted figure in Wallachian Freemasonry, which reportedly owed inspiration to a conspiratorial system first applied by the Filiki Eteria during the early stages of the Greek Independence War; other people involved in this subversive movement were, among others, Câmpineanu, Heliade Rădulescu, Mitică Filipescu, Nicolae Bălcescu, Eftimie Murgu. After Câmpineanu was defeated, Vaillant rallied with a conspiracy formed around Filipescu; on November 18, 1840, as authorities clamped down on Filipescu's movement, he fled Bucharest, heading for the Moldavian capital of Iaşi. According to Iorga, Vaillant's involvement with the revolutionary milieu, and especially with Filipescu and Heliade Rădulescu, had made him the object of suspicion. It was in Iaşi that he became an associate of Kogălniceanu, after taking an interest in Moldavian chronicles which the latter was reviewing and publishing; later, it was proposed that Vaillant's 1844 volume, "La Roumanie", featured sections of text actually contributed by the Moldavian writer. On June 19, 1841, the Wallachian Assembly voted to expel him indefinitely from the country for his role in Filipescu's revolutionary attempt.