France’s most famous Nazi hunters, Serge Klarsfeld and his German wife Beate, received top honors in a ceremony led by French President Emmanuel Macron this week.

Serge Klarsfeld, 83, received the Grand Cross of the Legion of Honor, France’s highest award, while the 79-year-old Beate Klarsfeld received the National Order of Merit, having already been decorated with the Legion of Honor in 2014, with the rank of Grand Officer.

Born September 17, 1935, in the Romanian capital Bucharest, Serge Klarsfeld escaped the Holocaust after his family moved to France but saw his father taken away to die in the Auschwitz Nazi concentration camp.

He was naturalized in 1950, and 10 years later, while studying at the prestigious Science-Po university in Paris, Klarsfled met Beate Kuenzel, the daughter of a former German soldier, on a metro platform.

The two, who married three years later, decided to bring fugitive Nazis to justice, a mission they pursued for more than half a century.

The Chief Rabbi of France, Haim Korsia, was among those who attended the ceremony at the Elysee Palace limited to family and close friends and associates.

n one of their most high-profile cases, the Klarsfelds found the notorious Nazi war criminal Klaus Barbie, a former Gestapo officer known as the “Butcher of Lyon” for his wartime torture of prisoners, who had escaped to South America.

In 1971, the Klarsfelds revealed that Barbie was living in Bolivia, and in 1983 he was extradited to France. Four years later he was convicted in a trial, and later died behind bars.

They also pursued members of France’s collaborationist Vichy regime, including Rene Bouquet, Jean Leguay and Marice Papon—despite obstruction from president Francois Mitterrand.

Mitterrand’s successor Jacques Chirac finally recognized France’s role in the deportations, a declaration Serge Klarsfeld said owed much to his and Beate’s campaigning. “Neither could have succeeded without the other,” their daughter Lida once said.