Rousseau was born in 1919 in Brittany, the daughter of a World War One veteran and French Foreign Ministry official. She was a brilliant linguist and graduated in languages in 1939.
With the outbreak of the war, Rousseau moved to Dinard on the coast of Brittany and became an interpreter for the German occupying forces. It was then that she became an intelligence agent even before she had made contact with the Allies.
Rousseau’s activities raised suspicions and she was arrested by the Gestapo in 1941. She was able to talk her way out of it and was released but on condition that she did not stay in the coastal area.
Instead, she moved to Paris to work for a company that supplied materials to the Germans and her official intelligence work began through a chance meeting on a train with French resistance leader Georges Lamarque who had been a fellow student in Paris. He asked Rousseau to join his ‘Druid’ network and she readily agreed.
She began to send regular reports back to Britain and in 1943 these included two on the German rocket research at Peenemunde. This alerted the British to the potential threat and led to the bombing raid in August 1943 and subsequent raids in 1944.
All that the Britsh new of the source of this information was that it came from ‘one of the most remarkable young women of her generation’ but such work was extremely risky and Rousseau’s position became increasingly compromised. The British planned to evacuate her shortly before D-Day but instead, she was arrested by the Gestapo and held at the Ravensbruck, Königsberg and Torgau concentration camps.
She survived her imprisonment and was rescued by the Swedish Red Cross shortly before the end of the war. Suffering from tuberculosis, she was sent to recuperate in Sweden where she met her future husband Henri de Clarens who had also been an inmate of the concentration camps.
After the war, Rousseau worked as a freelance interpreter for the United Nations but the story of her contribution to the war effort remained largely unknown. She was presented with the CIA’s Agency Seal Medal in 1993 and more details of her remarkable story emerged in the late 1990s.
She died in August 2017 at the age of ninety-eight and below is a recording from Public Radio International at the time of her death.