In 1906 she founded l'Avenir social, an orphanage for workers' children, which she ran despite government opposition until 1922, when she resigned after the board was taken over by Communists.

This inspired Madeleine to write a series of articles on "Bureautins" in Charles Guieysse's Pages libres journal in which she denounced the misery of foster children and the abuse tolerated by the administration.

The brochure denounced marriage, source of hypocrisy and sorrow, and affirmed the value of true love without chains or social obligations.

[3] She contributed to Libertaire and Temps Nouveaux during the pre-war years, writing against the extremes of the neo-Malthusian doctrine which led to either reduction or elimination of births.

[1] On 1 May 1906, thanks in part to her mother's savings, and helped by her sister and her companion Louis Tribier, Madeleine Vernet was able to found the orphanage l'Avenir social in a small house in Neuilly-Plaisance, Seine-et-Oise.

The orphanage was supported by the donations of friends, assistance from the cooperative La Bellevilloise, and subscriptions from Humanité and Guerre sociale.

[1] During World War I (1914–1918) Madeleine Vernet was forced to leave Épône for a period and move to the "colony of children of mobilized troops" in Étretat, Seine-Inférieure.

[4] She clandestinely circulated the poem Pour les venger (To avenge them) which she dedicated to "all our missing comrades ... victims of error."

[6] Madeleine Vernet gave a home to the eldest son of Marie and François Mayoux, who had been imprisoned for anti-militarist propaganda, and organized a defense committee for the teacher Hélène Brion, secretary of the Épône board.

She wrote, "From this tissue of infamies it came out that Hélène Brion was a dangerous and suspicious character--Anarchist, revolutionary, Malthusian, anti-militarist, defeatist.

[7] Madeleine Vernet distributed a clandestine brochure and two numbers of Les Voix qu’on étrangle, a pacifist sheet.

Vernet argued that on the contrary the state should assist unwed mothers, and wanted maternity to be recognized as a real job.

"[10] Madeleine Vernet founded the Ligue des femmes contre la guerre (League of Women against War) in Paris in 1921, with about 500 members at time of creation.

In April 1935 Vernet was elected to the steering committee of the Internal League of Fighters for Peace (Ligue internationale des combattants de la paix).