The historical literature on the first world war has devoted relatively little attention to the Allied blockade of the Central Powers. The few published studies have concentrated either on the blockade's naval aspects or exclusively on the British contribution. Little effort has been made heretofore to distinguish the French role. This study focuses on the French contribution to the diplomatic, as contrasted with the maritime, blockade of the Central Powers. It discusses primarily French relations with the so-called European border neutral states : principally Switzerland, but also the Netherlands and the three Scandinavian countries. Only in the diplomatic aspects of the Allied blockade program did the French play a distinctive role. Their token contribution to maritime blockade activity remained subordinate to the British. An examination of Franco-neutral rela­ tions involves not only a study of those diplomatic contacts per se but also a comparison of French and British tactics as a reflection of differing economic warfare concepts. This study also investigates the development of a French blockade organization to meet the demands of this new weapon, the diplomatic blockade.