In the second half of the eighteenth century, the marquis de Mirabeau, known across Europe as « the friend of men » and the first disciple of the physiocratic school, was linked to political elites in the Grand Duchy of Tuscany, and took a close interest in the reforms introduced by the government of Pierre-Léopold. In 1769, the relationship between the Grand Duke and the physiocrats was consolidated officially by Mirabeau’s decision to dedicate his new work, Les économiques, to the Prince of Florence. He then proposed to the man he dubbed the « Salomon of the midi » or even « the pastor prince » to use this manual in his exercise of power. This article aims to underscore the central place, still little studied, held by Mirabeau in the reception and application of physiocratic theories by the leaders of Tuscany, as well as to examine the benevolent perception of the monarchs,  administrators, and thinkers in the European Enlightenment towards of the politics of reform undertaken by Pierre-Léopold.