Have the incidences of a devaluation of the franc varied over twenty years? - In the course of the last twenty years, the French economy has become more and more open to international trade, the product structure of its foreign trade has been modified, its export-import ratio has declined, and its foreign debt has grown. What are the consequences of these transformations on the effects of a devaluation of the franc? The DMS model was used to evaluate them through simulations which, by leaving aside related policies and constraints linked to successive exchange regulations, aim at assessing the ,,pure" effects of a devaluation. First of all, the idea that the evolution of import and export structures would have left the volume of foreign tra...