When the Nazis marched into eastern France, he fled with family members to the southwest and changed his last name to Marceau to hide his Jewish origins.
With his brother Alain, Marceau became active in the French Resistance, altering children's identity cards by changing birth dates to trick the Nazis into thinking they were too young to be deported. Because he spoke English, he was recruited to be a liaison officer with Gen. George S. Patton's army.
His father was sent to the Auschwitz concentration camp in 1944.
"Yes, I cried for him," Marceau said. But he said he also thought of the others killed.
"Among those kids was maybe an Einstein, a Mozart, somebody who (would have) found a cancer drug," he told reporters in 2000. "That is why we have a great responsibility."