Relevance of multilayer approach and isotopic signal in the understanding of soil respiration in forest ecosystem. Soil CO(2) efflux is one of the most important flux in carbon cycle. Its amplitude is estimated to 68 +/- 4 Pg C per year. In temperate forest, it represents approximately 60-80% of total CO(2) emissions from the ecosystem (ecosystem respiration). Given its magnitude and the consequences of any amplitude change on the atmosphere carbon dioxide content, it is essential to improve knowledge of the mechanisms that govern it and know precisely the influence of environmental variables (edaphic and climatic). This paper aims to show the interest of conducting multilayer analysis of the mechanisms causing this flow (transport and production) rather than restricting the study to the soil surface. In addition, this article highlights the isotopic tool benefits to improve the mechanistic understanding of this efflux.