French actor-singer Yves Montand is making political waves in Gen. Augusto Pinochet's military-ruled Chile this week. "I had to come here to support the efforts to restore democracy in this country," Montand told reporters Monday upon his arrival from Paris. Montand starred in the 1969 anti-repression film "Z" by director Costa-Gavras--who also made "Missing," which dealt with the military dictatorship in Chile. (Jack Lemmon starred in that one.) Montand said he wanted to see the Chilean situation before the Oct. 5 referendum, in which Pinochet, who has ruled since 1973, seeks reelection for another eight years. Montand is also scheduled to visit the independent Human Rights Commission and La Victoria, a slum in Santiago, the capital, noted for its militant opposition to the military regime.