Cette recherche rend compte des difficultés de la diffusion des idées néo-libérales dans la vie politique française de 1974 jusqu’à 2012. Son premier apport consiste à démontrer – à travers un large panel de données sur les politiques publiques, l’opinion publique et les programmes des partis – qu’en France le succès des idées néo-libérales a été moindre par rapport aux autres pays européens. Son deuxième apport consiste à expliquer cette anomalie française, en contribuant plus généralement à la question de la diffusion des idéologies dans un système politique. La réponse se base sur une double étude : une analyse micro-historique centrée sur les acteurs (à partir d’entretiens et d’un travail sur les archives des organisations internationales de promotion du néo-libéralisme), couplée à une analyse macro-sociologique centrée sur les caractéristiques du contexte national. Il est montré que si la diffusion du néo-libéralisme a été moins importante en France par rapport à d’autres pays voisins, c’est en raison de la forte résistance de l’opinion publique à son égard. Celle-ci a restreint la fenêtre d’opportunité de ses partisans de manière directe en incitant les hommes politiques à ne pas mettre en œuvre des politiques publiques trop congruentes avec cette idéologie, et de manière indirecte, en exerçant une influence sur le discours économique et social des principaux partis politiques pouvant légitimer la mise en œuvre de mesures libéralisant les politiques publiques. De plus, la structure des institutions françaises a renforcé l’effet de « dépendance au sentier » dans la fabrique des politiques publiques en valorisant l’expertise d’État contre celle d’acteurs susceptibles de remettre en cause le consensus existant comme les universitaires et les think tanks. Enfin, à partir de la réalisation d’une socio-histoire inédite du mouvement néo-libéral depuis les années 1970, d’autres facteurs plus contingents sont identifiés. La fragmentation et la radicalité des partisans du néo-libéralisme, ainsi que la quasi absence d’entrepreneur politique susceptible d’incarner ces idées, ont contribué à la marginalité de ces idées dans le débat public. / This thesis examines, and then explains, the relative lack of success in the dissemination and acceptance of neo-liberal ideas in French politics during the period from 1974 to 2012. Using a wide range of data on public policy, public opinion and political party platforms, it demonstrates that neo-liberal thought has had far less influence in France than in other European nations. It then accounts for this anomaly and contributes more generally to the understanding of how ideologies diffuse in a political system. The answer is derived from the combination of two perspectives. The first is a stakeholder-centered, micro-historical analysis based on interviews and on the archives of international organizations promoting neo-liberalism. This is coupled with a macro-sociological analysis focused on the characteristics of the French national context. The failure of neo-liberalism to propagate in France is shown to be mainly due to the strong resistance of public opinion towards it. This has restricted opportunities for its supporters, both directly, by discouraging politicians from implementing policies congruent with this ideology, and indirectly, by shrinking the policy window of acceptable economic and social discourse and thus limiting the options of the main political parties that might otherwise legitimize the implementation of neo-liberal public policies. In addition, the structure of French institutions has reinforced the effect of "path dependence" in the making of public policy by valuing state expertise above that of actors likely to question the existing consensus, such as academics and think tanks. Finally, we identify other more incidental factors: The fragmentation and radicalism of neo-liberalism's supporters, as well as the absence of any political actor who could effectively embody these ideas, contributed to their marginality in the public debate.This thesis examines, and then explains, the relative lack of success in the dissemination and acceptance of neo-liberal ideas in French politics during the period from 1974 to 2012. Using a wide range of data on public policy, public opinion and political party platforms, it demonstrates that neo-liberal thought has had far less influence in France than in other European nations. It then accounts for this anomaly and contributes more generally to the understanding of how ideologies diffuse in a political system. The answer is derived from the combination of two perspectives. The first is a stakeholder-centered, micro-historical analysis based on interviews and on the archives of international organizations promoting neo-liberalism. This is coupled with a macro-sociological analysis focused on the characteristics of the French national context. The failure of neo-liberalism to propagate in France is shown to be mainly due to the strong resistance of public opinion towards it. This has restricted opportunities for its supporters, both directly, by discouraging politicians from implementing policies congruent with this ideology, and indirectly, by shrinking the policy window of acceptable economic and social discourse and thus limiting the options of the main political parties that might otherwise legitimize the implementation of neo-liberal public policies. In addition, the structure of French institutions has reinforced the effect of "path dependence" in the making of public policy by valuing state expertise above that of actors likely to question the existing consensus, such as academics and think tanks. Finally, we identify other more incidental factors: The fragmentation and radicalism of neo-liberalism's supporters, as well as the absence of any political actor who could effectively embody these ideas, contributed to their marginality in the public debate.