One of the steps making it possible to increase the quality and the reliability of the software executing on distributed systems consists of the use of methods of software engineering that are known as formal. The majority of the formal methods currently existing correspond in fact more to formal specifications languages than to methods themselves. This is due to the fact that the two fundamental aspects which are: the logic of use of the language and the coverage of the software life cycle are not, for the majority, defined. The development by stepwise refinement is one of the means making it possible to define these two aspects. This thesis aims to the definition of the concepts of refinement and implementation of model-oriented formal specifications. It brings a methodological base making it possible to use such a specifications language during a development by stepwise refinements and during the implementation stage. This thesis defines...