Casimir Perier married (13 October 1805) Marie Cécile Laurence Loyer, nicknamed "Pauline", the daughter of Laurent-Pouthus Loyer, an old regime magistrate of Lyon who was a victim of the Terror during the Revolution. There were two sons: Auguste Casimir-Perier (1811–1876), deputy for Seine and Aube, and Charles-Paul Perier (1812–1897), deputy and senator for Seine-Inférieur. Auguste-Casimir's son, Jean Casimir-Perier (1847–1907), was elected President of the Third Republic in 1894.
