Historically, trade unions were formed within national boundaries. However, the major changes taking place all over the world have thoroughly affected their practices and their activities. Since their onset, unions have gathered together in international organisations in order to pursue common goals. The relations between trade unions at the international level are beforehand an opportunity to exchange broad " views of the world " but also practical resources which enrich and strengthen the role they play nationally. The dissertation covers a century of history of the French trade unions analyzed from this international point of view. First, it shows the influence of this international perspective on the founding and evolution of the French unions, in other words the outside influences which have contributed to shaping its main features. Then, the role of the three major French unions CGT, CFDT and CGT-FO in the construction of Europe after the second World War is demonstrated. The construction of Europe has forced the unions to look beyond national borders and more specifically within the European community. The three unions have responded each in its own way. Their international commitment clarifies a great deal of their development. Looking out from within : the evolution of the French unions does not reveal two separate sides of a universe but a complex combination of both. The international dimension is a key component which contributes to the role of trade unions within their own nation. Analyzing social issues from this international perspective turns out to be extremely fruitful to explain some developments that national interactions alone cannot justify.
