The French discussion on pension funds has been confined to their capacity to reduce the consequences of demographic decline, overshadowing their other economic advantages over the defined benefit system. After having presented pension funds and their great diversity regarding benefits, joining, and exiting, the article explains their role in France and in the other advanced economies, as well as the underlying socio-economic stakes. It then expounds and critically analyzes the main arguments that have long been used in France to oppose their development. However, there seems to have been a shift with the creation, by the recent Sapin law, of the legal and prudential vehicle that is necessary for their development. It remains to give this vehicle a fiscal and social status that would allow it to play a genuinely complementary role to the defined benefit system, while helping to finance French businesses.