She moved to Berlin after World War I with her father to join the school of Russian ballet.
When the Nazi Party rose to power in 1933, she moved to France to flee antisemitic persecution.
She was a successful chanteuse, parodist, cabaret singer, and actress, best known for her role as Pirate Jenny in director G. W. Pabst's 1931 French-language adaptation of Bertolt Brecht and Kurt Weill's Threepenny Opera (Die Dreigroschenoper).
She appeared in several French films until the early 1970s, including Docteur Françoise Gailland, L'Humeur Vagabonde, La Faute De L'Abbe Mouret, Le Petit Matin, Le Fou Du Labo, Julie La Rousse, and the French romantic melodrama Martin Roumagnac, which starred Marlene Dietrich.
[citation needed] Lion and Dietrich sang a famous duet, "Wenn die beste Freundin mit der besten Freundin", a song which allegedly had lesbian overtones.