In 1940, Laure joined the "A.V." (Army of the Volunteers) resistance network of Dr. Bareiss in annexed Alsace and became a special agent under the name "Mado". Her assignment was to hide escaped war prisoners at her home in Alsace before helping them to escape to France.
Just before Christmas 1941, she was hidden in a locomotive and secretly brought to the free south of France. There she worked as an administrative assistant in the service which works with refugees from Alsace and from 1942 she collected information for the Resistance network "Mithidate" before encoding them and sending them to London by post mail.
On January 31, 1942, Laure married Eugène Diebold, who also escaped to Lyon. In July of that year they were arrested and later released by the Gestapo. They moved to Aix-les-Bains where Laure became known only as "Mona".
In September 1942 Laure was promoted to the rank of Lieutenant of the Free French Forces. She was assigned to the position of private secretary of Jean Moulin. After his arrest in 1943, she was sent to Paris to be the secretary of Georges Bidault.
She was arrested again on 23 November 1943 with her husband and sent to Fresnes Prison. She was not tortured because she convinced her Nazi captors that she was just a secretary and not a major figure in the Resistance network. Nevertheless, she was sent to the Schirmeck Nazi camp. Between January 1944 and her liberation in April 1945 she was transferred to Auschwitz, Ravensbrück and Buchenwald.
Laure died in Lyon on 17 October 1965 in Lyon and, in accordance with her last wishes, was buried in her childhood place Sainte-Marie-aux-Mines in Alsace.