http://starlutz.com/blog/ — Classic cinema reviews & clips.
Suzy Kendall stars as a morphine-addicted German spy in the classic WW1 romantic espionage drama Fräulein Doktor (1969).

After a successful undercover mission in Scotland to arrange the assassination of Lord Kitchener, the beautiful and enigmatic young woman known only as Fräulein Doktor moves on to her next target – a new poison gas being developed for trench warfare by the Allies.

Brilliant female chemist Dr. Saforet (Capucine) holds the secret of the gas. Insinuating herself as a maid in her household, Fräulein Doktor sets about seducing the older woman into a lesbian affair…

source