Elsbeth Schragmüller (7 August 1887, Schlüsselburg near Petershagen, Kingdom of Prussia, German Empire — 24 February 1940, Munich, Nazi Germany), also known as Fräulein Doktor and Mademoiselle Docteur, as well as Fair Lady, La Baronne and Mlle.
After the outbreak of the First World War, Schragmüller moved to occupied Belgium, where the German governor general, Field Marshal Colmar von der Goltz, assigned her to Section VII, wherein she worked first as part of a postal censorship team who opened and read private letters in search of coded messages from members of La Dame Blanche spy ring to British Intelligence.
She later switched to intelligence collection and worked, after a short training period, in Lille for the General Staff's counterintelligence wing, Abteilung IIIb.
After the November Revolution of 1918, Schragmüller returned to civilian life, resumed her academic career, and became the first female assistant chair at Freiburg University.
For many years, she was invariably known as Mademoiselle Docteur or Fräulein Doktor, her actual name being revealed only in 1945 from German intelligence documents captured by the Allies after World War II, when she had already died of miliary tuberculosis in 1940.