Marthe Cohn was born into one of seven children living just across the German border in France when Hitler rose to power. As the Nazi occupation escalated, Marthe’s sister was sent to Auschwitz while her family fled to the south of France.

In November 1944, after the liberation of Paris, Marthe Cohn enlisted and became a member of the Intelligence Service of the French 1st Army, commanded by Marshal of France Jean de Lattre de Tassigny. After 14 unsuccessful attempts to cross the front in Alsace, she crossed the border into Germany near Schaffhausen in Switzerland. As a nurse fluent in German, she assumed the identity of a German nurse and claimed she was searching for her missing fiancee. She would then crawl back across the Swiss border to relay the information back to the French intelligence.She was able to report to her service two major pieces of information: that northwest of Freiburg, the Siegfried Line had been evacuated and where the remnant of the German Army laid in ambush in the Black Forest.