Over the course of his life he edited several publications: Ce qu’il faut dire, Le Libertaire, Défense de l’Homme and Liberté.

In 1921, at the congress of the CGT in Lille, faced with strong-arm threats from the leadership, he fired his revolver in the air so that the revolutionary syndicalists could express themselves.

After the declaration of World War II, Lecoin penned a tract entitled "Paix immédiate".

After the war, Lecoin founded the committee to support Garry Davis in introducing a worldwide citizenship.

On the 21st day, prime minister Georges Pompidou sent him a promise that a legislative bill was about to be submitted to the Parlement.

Though a committee developed to recommend Lecoin for 1964 Nobel Peace Prize, he retracted his name to support (eventual laureate) Martin Luther King Jr.'s candidacy.