Falkenhayn was born in Berlin to the noble Zollikofer family, which for centuries had held Altenklingen Castle in the Swiss Thurgau region.
In the late 1920s, Falkenhayn became friends with the Polish intelligence agent Major Jerzy Sosnowski, whom she had met at the horse races, and became his lover.
He made her socialise with employees at the Ministry of the Reichswehr to obtain secret documents concerning the preparations for a German Invasion of Poland.
At least from 1932, her activities were monitored by the Abwehr intelligence agency, and upon Sosnowki's exposure on 27 February 1934, Falkenhayn was arrested together with her friend Renate von Natzmer, his other lover.
Their executions were carried out by Carl Gröpler[2] and were, however, not the last by axe; the last legal manual beheading in Germany is believed to be that of Olga Bancic, in 1944 during the war.