This thesis aims to analyze the impact of the creation of the West African Economic and Monetary Union (WAEMU), a regional trade agreements (RTAs) example on the dynamics of trade and development in this area. It analyzes the process of real convergence and examines opportunities to strengthen the integration process. The first chapter focuses on the impact of integration on reducing disparities in per capita income between member countries. Measured by the standard deviation of per capita GDP at constant prices of 2005, these analyzes revealed that the WAEMU countries are experiencing a real convergence between 1970 and 2010. However, according to our analysis, the creation of teh WAEMU has not significantly improved living conditions in memeber countries. The idea expressed in the first chapter is a regional trade agreements (RTAs) which brings together more or less equal partners and aims not only to promote trade themselves, but also and especially the integration and developemnt, may be a useful adjunct for multilateralism in the sense that it allows to correct inefficiencies and absorb its impact. On the other side, some RTAs can pose serious threats to the multilateral trading system from the moment they generate imbalances and reinforce inequalities between those who sign them. This is the case of many RTAs involving developing and developed countries. The second chapter focuses on one example of this type of RTAs and proposes a strategy to reduce the negative effects and to enable developing countries to reap the benefits of free trade. The analysis is done on the macroeconomic implications of economic partnership agreements(EPAs) between the countries of the European Union and those of the African Caribbean and Pacific. We show, using data from Côte d'Ivoire that, with productive public spending, developing countries can reudce the negative effects of short-term EPA. Developing countries are so small and too weak to cope with foreign competition that they implement protectionist policies such as the introduction of a tariff on imports. This is the case of the common external tariff imposed by the WAEMU imports from third countries. Chapter three of this tesis proposes a simple DGSE model, to assess macroeconomic impacts of this change in tariff structure. It appears that the net effect of a tariff reduction is the decrease of the main components of domestic demand and a lower level of consumer utility. The analysis shows that the dynamics of medium and long term as well as the instantaneous reaction of theses components depend on the elasticity of substitution between varieties of imported goods.