Th e paper concerns the system of government adopted in the French constitution of 1958 and its evolution in subsequent years. Some attention is given to the origins of the Fift h Republic, which was perceived by the most important creators of the aforementioned constitution as a renewed parliamentary regime. Th e evolution of this system took place in two ways. First of all, its shape has been set by some constitutional amendments (e.g. the introduction of the general presidential election as well as the shortening of the presidential term to fi ve years). Secondly, these changes have been complemented by the practice of exercising power (e.g. the emergence of informal political responsibility of the government to the head of state). Th e unwritten rules of political life have consequently become an equally important component of the system of government. Th is, in turn, contributes to some diff erences as to how the system of government applied under the Fift h Republic should be defi ned. At the constitutional level the regime still seems to be quite close to the parliamentary model, but in political practice it gains the characteristics of semi-presidentialism based, inter alia, on double political responsibility of the cabinet.