ECLAIRs is a microsatellite devoted to the multi-wavelength observation of the prompt emission of GRBs. For about 100 GRBs per year, ECLAIRs will provide high time resolution high sensitivity spectral coverage from a few eV up to a few hundred keV and localization to 10' in near real time. This capability is achieved by combining wide field optical and X-ray cameras sharing a common field of view with a coded-mask gamma camera providing the trigger and the localization of the bursts. ECLAIRs relies upon an international collaboration involving theoretical and hardware groups from Europe and the United States. In particular, it builds upon the extensive knowledge and expertise that is currently being gained with missions such as HETE-2 and INTEGRAL.