In the modern democracies, the polysemic concept of solidarity has been one of the references allowing the construction of social rules and institutional frameworks in which the market economy has been embedded. The so-called Fordist compromise between market and welfare state was an emblematic example of such an embededness. After the end of this compromise, the text suggests the following hypothesis where the notion of sustainable development becomes central to imagine a new phase of compromise between economy and society. But this notion implicitly evokes two contrasted projects, one based on “philanthropic” solidarity, the other one based on “democratic” solidarity. It is possible to better understand the role of corporate social responsibility when referred to these two projects, reactualizing constant debates about solidarity.