In the assembly, Calès sat with the extreme-left group of the Mountain (French: "La Montagne," whose members sat on the highest benches of the Assembly), like his uncle Jean-Marie Calès half a century before (in 1792) at the National Convention. This group, in 1848, was led and organized by Alexandre Ledru-Rollin and comprising sixty-six deputies such as Pierre-Joseph Proudhon, Pierre Leroux, Victor Schœlcher or Félicité Robert de Lamennais, some of the pioneers of socialism in history. Calès attempted to defend the political achievements and the important social benefits obtained after the Revolution of February 1848 against the attacks of the moderate Republicans and of the party of Order (a political group formed by monarchists and conservatives, led by prominent members including Adolphe Thiers, Francois Guizot, Odilon Barrot, and Alexis de Tocqueville), who were the majority in the assembly. Thus, Calès violently opposed the reactionary policy of the Assembly and voted constantly with the "montagnarde" left and often with the associated independent extreme left (in particular with deputies such as Étienne Arago, Victor Considerant et Edgar Quinet).