Born Marthe Betenfeld in Blamont, France in 1889, the daughter of a brewer.
An excellent student, she excelled at languages, eventually learning to speak English, Spanish and German in addition to her native French. She was also adventurous, excelling as an aviator, almost unheard of for a woman at that time.
Married Henri Richer, a pilot serving in World War I, in 1914. Was approached by French counter-intelligence at about this time and was recruited for service based on her langiage skills as well as her daring personality. After her husband was killed in battel, Marthe distracted herself from her grief by travelling to Spain to undertake intelligence duties. Became a familiar face within the social elite of German society within Spain and was introduced to the acting chief of the Abwehr. He suggested to Richer that she should work as an agent of the Abwehr, returning to France and spying on behalf of the Germans. Richer told him that she would only consider doing so if the offer was extended by the head of the Abwehr in France himself. So eager were the Germans that they agreed and the offer was so extended. Fortuitously, the Abwehr chief in France, Baron Hans Kron. Kron, who was also the German naval attache in Madrid, fell in love with Richer and they became lovers soon thereafter.
Richer was shipped off to France to gain information on armaments production. She was provided with a new kind of security device, an invisible ink that was contained within a capsule the size of a grain of rice. Upon arrival, she disclosed the invisible ink to her French superiors and informed them that she was involved with Kron. She was given doctored information about armaments production and was sent back to Spain.
In Spain, she re-established her relationship with her lover. She also learned that he had been involved with Mata Hari, the notorious spy who was staying ater the same hotel as Richer. Threatening to break off her relationship with Kron, Richer was able to draw the lovestruck attache even deeper into her web, thus gaining access to even more secret information, which she passed back to the French, including revelations about submarine development.
Richer was sent across the globe on missions but eventually grew tired of the deception and the pressure. Eventauly she decided to return home to France but first confessed her duplicity to Baron Kron. After retiring from active service, Richer was generally ignored by the French government, based in part from unfavorable attention to her long-running relationship with the German attache. Eventually, however, her services were recognized and she was awarded the Legion of Honor medal in 1933.
Took part in the French resistence during World War II and died in 1982.