This introductory article reflects on the new momentum that political radicalism has taken on in France. The ebb and flow of radical aspiration featured regularly in French politics under the Fourth and early Fifth Republics, before the failure of the "Socialist experiment" in the early 1980s brought about a paradigm shift. In the wake of this failure and with the "end of ideology" supposedly in sight, political leaders and parties tempered their appeals to radical solutions and conspired, not least through recurrent power-sharing, to vacate mainstream political discourse of much of its former radicalism. Since the presidential election of 2007, however, there has been a marked return to promises of radical change as the common currency of political discourse across the full left-right spectrum in France. This article introduces a special issue of French Politics, Culture & Society that brings together scholars from France, Britain, and Canada to discuss some of the meanings, expressions, and prospects of political radicalism in France today.