The film is based on the memoirs of Andr Devigny, a member of the French Resistance held in Montluc prison by the occupying Germans during World War II.
The film is based on the memoirs of Andre Devigny, who escaped from the Montluc prison in Lyon in 1943, during World War II. Andre Devigny (25 May 1916  12 February 1999) was a French soldier and member of the Resistance. Built in 1921 for use as a military prison, after the invasion of the unoccupied zone of Vichy France in November 1942, the Gestapo used it as a prison, interrogation centre and internment camp for those waiting for transfer to concentration camps. The Geheime Staatspolizei (Secret State Police), abbreviated Gestapo (German: [tapo; /stpo/), was the official secret police of Nazi Germany and in German-occupied Europe. 
