In French law, there is no constitutional or legislative disposition that defines the concept of public establishment. The definition of the concept is made with common characteristics in all public establishments. Accordingly, public establishments have administrative and financial autonomy, dedicated to a task determined according to the principle of specialty; but they are public personalities that are subject to the tutelage control of the state or local administrations, that have a special duty and are subject to a legal regime. The common characteristics in this definition are determined by considering the legal regimes of public establishments. This legal regime is directly related to the creation of public establishments. According to article 34/2 of the 1958 French Constitution, the rules regarding the categories of a public establishment can only be determined by code. The administration can only create a public establishment in a category previously regulated by code through an administrative act. The administration cannot create a new category of the public establishment. The power to create a new category of public establishment also includes the power to determine the legal regime. In France, the legislature has the authority to determine the legal regime of public establishments, thus the meaning and scope of the concept. In French law, it would not be wrong to say that with this authority, the legislature has the authority to determine the administrative organization and administrative function. Keywords: Administrative Law, Administrative Organization, Public Establishment.