She also opposed the divorce proceedings in place at that time, and considered the rights of a child born out of wedlock to be inadequately defined.
[1] In addition, Mazirel worked as tour guide, which led her to visit Paris during the 1937 world's fair and attend a large international conference where German scientists presented plans for a "racial hygienic cleansing".
Her office on Prinsengracht canal served as a cover for resistance activities, such as making contact, passing along messages and providing shelter to refugees and people hiding from the Nazis (so-called onderduikers).
Her excellent command of German allowed her to make contact with high-ranking Nazi officers such as SS-Hauptsturmführer Ferdinand aus der Fünten.
However, she failed to convince Abraham Asscher, chair of Amsterdam's Jewish Council, of this, even when she declared that she had obtained this information from Aus der Fünten himself.
Soon after, her Jewish husband and their children Leo and Wolf were forced to go into hiding to escape arrest and transportation to the extermination camps.
She was one of the originators of the term homofiel (homophile) to replace homoseksueel (homosexual), in order to place more emphasis on love than on sexuality.
[1][2] Mazirel also worked as an attorney for the Nederlandse Vereniging voor Sexuele Hervorming (NVSH, "Dutch Society for Sexual Reform").
[1] On 16 November 1950, she entered a pro forma marriage with her second husband, film operator Robert Jean Hartog, with whom she had served in the resistance.
In 1955, she and her husband moved to the French countryside due to her worsening health, a consequence of the violence she had endured during her time in the resistance.
From France, she fought against the 1968 Woonwagenwet legislation to regulate Romani, which she considered racist, and also opposed the 1971 census which she believed collected too much personal information.