Buildings have a significant impact on the environment throughout their life cycle. They are a major responsible for exhausting valuable natural resources and polluting the atmosphere through the emission of greenhouse gases. Nowadays, a high interest is manifested worldwide in constructing green buildings so that to limit the harm caused by human habitations on the ecosystem. In this scope, sustainable design is thus a primary thrust area. However, the development of eco-design tools as well as their implementation by building experts is still limited. In this paper, we investigate the eco-design practices as adopted nowadays by building designers and constructors in France. By using the results of a qualitative survey, we analyze how the environmental issue is considered in the decision-making process. Later on, a proposition of how and which stage eco-design tools could be implemented is discussed.