[1] Chassain served as Deputy for Bouches-du-Rhône's 16th constituency in the 12th legislature of the Fifth French Republic [fr] as a member of the Union for a Popular Movement.
As a member of the National Assembly, he fought for the reestablishment of the death penalty for acts of terrorism.
[3] During the 2012 Union for a Popular Movement leadership election, Chassain supported Jean-François Copé to be leader of the party.
Following a contested election, he called for Nicolas Sarkozy to be President of the UMP, and for Copé and François Fillon to be co-presidents.
[4] In a December 2012 interview with Minute, Chassain called for more unity between the UMP and the National Front.