Becoming increasingly militant, she befriended journalist and feminist Marguerite Durand but, following a confrontation with the Marxist Jules Guesde, left the newspaper in 1888.

She continued writing for other papers in which she promoted women's emancipation and denounced social injustices, including the Dreyfus affair.

[3] A staunch leftist, Rémy backed a number of anarchist causes, including the defense of Germaine Berton, and participated in the 1927 efforts to save Sacco and Vanzetti.

She supported the Russian Revolution of 1917 and, in 1921, joined the French Communist Party, resigning a few years later in order to maintain her membership of the Human Rights League.

Caroline Rémy died in 1929 at her home in Pierrefonds, Oise department in the Picardy region of France.