The French socialist movement developed out of an eclectic mixture of ideas and militant groupings in the late nineteenth century. As party unity developed, many theoretical positions were sidelined. The strand of thinking exemplified by the working-class journalist Eugène Fournière, an advanced form of economic federalism that drew on the writings of Pierre-Joseph Proudhon, found it difficult to identify itself clearly in twentieth-century socialism; yet this strand has remained a source of fruitful discussion. This article attempts to unpack the relationship between the intellectual history of these forms of socialism and the issues of political identity faced by militants who were attempting to forge a clear identity. Using Fournière as a case study, this article suggests that a fresh examination of the political culture of the socialist movement will give a stronger basis for understanding how dissidence and libertarianism have been vital elements in French socialism.