Key defendant, former vice president at Airbus parent company EADS, Jean-Louis Gergorin, right, walks out the Paris court after the first day of the trial in the saga known as the Clearstream affair, Monday Sept. 21, 2009. France's former prime minister, Dominique de Villepin, goes on trial Monday on charges he helped perpetuate a smear campaign targeting his longtime rival, President Nicolas Sarkozy.