In 1910 in Copenhagen, the 2nd International Conference of Socialist Women adopted the idea of an "International Women's Day" from a proposal by Clara Zetkin (German Social Democratic Party), although no date was set.
The "Journal du CNRS" notes that "Women's Day was therefore the initiative of the socialist movement and not of the feminist movement, which was very active at the time". The historian Françoise Picq adds that "it was precisely to counteract the influence of feminist groups on the women of the people that Clara Zetkin proposed this day", rejecting "the alliance with the 'feminists of the bourgeoisie'": https://lejournal.cnrs.fr/articles/journee-des-femmes-la-veritable-histoire-du-8-mars@histodons