Medium-size towns regularly feed a public debate and urban and geographical researches. The perpetual reccurence of public policies dedicated to medium-size town’s planning is an invitation to put them in a historical perspective. However, we have to articulate the long-term history of French urban system and the more contemporary history of town and coutry planning. It asks the question of the limits of crossover between geography and history. The concept of medium-size towns was created during the sixties by planners and geographers. It happears to be difficult to use it in the case of urban history, especially for the periods of pre-industry. In the opposite, an analysis of medium-size towns policy which only considers the contractual policies born during the seventies will probably go on to a nonsense about history of urban change.