Retracing the origins of the French movement La Fédération, this article aims at illustrating the metamorphosis of the personalist and communitarian third way in the 1940s : from « corporatism » to « federalism ». One of the first and main movements mobilizing in favour of a united Europe, La Fédération is also a product of the investments that paved the way for a national revolution under the Vichy regime. Analyzing the regroupings and reconversions which favoured the ideological and practical continuities of the third way, this article more generally aims at questioning the structure of political cleavages that arose in the postwar period regarding the European issue.