He met Lucie Bernard while participating in left-wing politics in Paris. They married on Dec. 14, 1939, in Dijon, after he warned her that it might be dangerous for her to marry a Jew.

“That just made me even more keen,” she said.

She joined the Resistance in October 1940, and he joined a month later. The couple settled in Lyon and founded Libération Sud, an underground network of Resistance fighters operating in southern France. Their principal activity was publishing the underground newspaper Libération. Mr. Aubrac was arrested twice before falling into Barbie’s hands. His parents died in the Auschwitz concentration camp.

After France was liberated in 1944, Mr. Aubrac was appointed commissioner to govern Marseille. But the rough justice he administered to Nazi collaborators during this period, called the “Epuration,” or purification, led to his dismissal in five months.

It did not end his involvement in public affairs, however. He was soon appointed to oversee the destruction of millions of mines around France. In 1958, the government of Morocco asked him to help in its economic development efforts, which he did for five years. He continued to work with less developed countries and took a position at the United Nations’ Food and Agriculture Organization in Rome.

When Ho Chi Minh, the North Vietnamese leader, came to Paris in 1946 to negotiate independence, he stayed in Mr. Aubrac’s home, explaining that he would have missed having a garden if he had stayed in a hotel. In 1967, as was later widely reported, the United States secretly enlisted Mr. Aubrac to travel to Hanoi to negotiate an agreement to end the Vietnam War. He failed, but an agreement similar to the one he helped fashion led to peace talks.

In 1975, Kurt Waldheim, the secretary general of the United Nations, used Mr. Aubrac as a channel to communicate with the North Vietnamese and Vietcong authorities during the war’s last throes.