Ernst Demuth, her father, was a member of the Furriers' Trades Union and a Social Democratic Party (SPD) official, but he died in 1912.
Erna Demuth trained and qualified at the Hamburg Fröbel College as a Kindergarten teacher, and it was in this profession that she worked for five years.
[3] Her activism included producing and distributing "revolutionary leaflets", as a result of which, on 27 March 1918, she was given a thirty-month prison sentence for alleged treason ("Landesverrat").
That same month her husband, who had also been expelled from the party in SPD, and had now been fatally wounded in the fighting, was placed in a battlefield hospital: here he died in June 1918.
She was a co-founder of the Hamburg branch of the newly emerging Communist Party, and she was the only female member of the 30 person leadership team of the city's Workers' Soviet/Council,[3] which worked closely with the Soldiers' Soviet/Council to create a combined Hamburg Workers' and Soldiers' Soviet/Council under the leadership of a fellow member of the radical left, Heinrich Laufenberg.
Erna Halbe later recalled that they nevertheless found themselves obliged to continue with the daily administration of the city: "The pressing problem was food supplies ... Day and night we sat and debated what to do ... We had been hoping for a real revolution.
In 1920 Erna Halbe was appointed Women's Secretary for the party regional leadership team ("Bezirksleitung") for the Wasserkante district, comprising Hamburg and a large surrounding area of Holstein to the north of the Elbe.
[3] Later that year she was sent to work for Red Aid ("Rote Hilfe Deutschlands"), the party sponsored worker's welfare organisation, running an orphanage in Elgersburg, some considerable distance to the south of Berlin.
Nevertheless, in order to attract defections from the communist movement a number of SPD members, and others, established the Socialist Workers' Party of Germany ("Sozialistische Arbeiterpartei Deutschlands" / SAPD).
Erna Halbe continued with her (now illegal) political work in Berlin till 30 May 1933 when the Gestapo searched her house and arrested her.
Back in Berlin, in 1938 the Gestapo learned of her activities from her political friends who had failed to escape in time, and demanded that she be handed over by the Czechoslovak government.
At this stage, not withstanding the very basic level of the accommodation, Gurs was not set up for enforced detention and inmates were able to leave the camp in the day time.
Joseph Lang, (who was Jewish) made his way to Lisbon, but Halbe was unable to obtain an exit visa from the French authorities, who were also holding on to her identity papers.
In the end she was able to catch up with Lang after a brief delay, but she achieved this only after crossing the Pyrenees on foot, carrying a forged birth certificate.