Cette histoire est celle d'un remembrement commercial (par analogie au remembrement agricole), encouragé dès 1963 par Valéry Giscard d'Estaing, ministre des Finances. En effet, prédominant jusqu'au début des années 1960, le petit commerce indépendant décline ensuite de manière continue et la grande distribution capitaliste se renforce, grâce notamment à des mesures d'aides au financement des investissements ou à des incitations fiscales (TVA). À partir de la fin des années 1960, l'effort de remembrement commercial n'est cependant plus univoque, car le mécontentement des petits commerçants s'amplifie et s'illustre parfois par des protestations violentes. Votée en 1973, la loi Royer est alors censée inaugurée une nouvelle politique d'équilibre entre les différentes formes de commerces. Elle se distingue cependant par ses effets pervers contraires aux objectifs annoncés et sa réforme revient de manière récurrente dans l'agenda politique jusqu'en 1996. / This thesis looks at retail trades' transformations in France, from 1945 to 1996. It opts for an institutional perspective and examines the state intervention in the sector. Archival collections from ministries, from the presidency of the Republic and from different central administrations were explored, and the state's action toward retail trades was studied as a sectorial policy. Hence, this work analyses, among other subjects, urban planning, commercial relationships between retailers and suppliers, professional training or the question of Sunday openings. This is the story of a retail amalgamation (remembrement commercial), encouraged as early as 1963 by Finance Minister Valéry Giscard d'Estaing. Indeed, predominant until the 1960s, small independent retailers then declined continuously while hypermarkets and big capitalistic retail developed, thanks notably to credit facilities and fiscal incentives (V AT). From the end of the 1960s, this amalgamation policy became Jess unequivocal as the discontent of small shopkeepers was rising, sometimes resulting in violent protests. In 1973, the Royer law was voted and claimed to insure an equilibrium policy for different forms of retail. Yet, this law was characterized by its unanticipated effects and the will to reform the law became recurrent in the political agenda until 1996.