This chapter is presented as a warning to demonstrate that “producing more with less” is at the origin of a series of failures that could go against its initial objective. It looks at the principles and conceptual limitations of “producing more with less”, better known as “eco-efficiency”. The chapter shows how they contribute, at a more global level, to its increasing complexity due, for example, to the emergence of environmental innovation, of the circular economy in the digital age. Public authorities and industrialists intensified their efforts to make eco-efficiency an environmental performance indicator. From the 1990s onwards, the analysis of eco-efficiency took on another dimension as part of a systemic approach. The chapter highlights the consequences of “producing more with less” at a macrosystemic level, especially the rebound effects. The rebound effects, for their part, are the result of an insufficient substitution effect between resources.