One of the inspirations for the film came when director Jean-Paul Salomé read "The Times" in London one morning whilst on post-production of Arsène Lupin: O Ladrão Mais Charmoso do Mundo (2004). Salomé saw a full page devoted to Lise Villameur, a French Resistance agent who worked for the SOE, the Special Operations Executive created by Winston Churchill during the Second World War. She had just died at the age of 98. She had been a real heroine and Britain paid tribute to her. Intrigued by her story, Salomé started doing some research with the help of historian Olivier Wieviorka. Salomé discovered that other women had been SOE agents. They were among the fifty or so agents of the "French Section" that were trained in England before working for the Allies in occupied WWII France.
According to the Cinema Intelligence Agency website, "The French title ["Les femmes de l'ombre"] translates as "Women of the Shadows" which could be mistaken for "Shady Ladies" hence the pragmatic English title of "Female Agents"."
The style and authenticity of the actors' hairstyles became a full-on obsession for director Jean-Paul Salomé during principal photography.
The action in the film is set in spring 1944, on the eve of the Normandy Landings. The decision to invade was taken at the Tehran conference (28th November - 1st December, 1943) and technical planning began in January 1944, which didn't leave the Allies much time to prepare. On the German side, there was no doubt that the Allies intended to land in north-western Europe. Hitler himself sensed that invasion was imminent in November 1943 and demanded that work on fortifying the coastline around Calais and Normandy be speeded up.
The film is "dedicated to the women who fought against Nazi barbarity".