Misère de la philosophie.

The Poverty of Philosophy (French: Misère de la philosophie) is a book by Karl Marx published in Paris and Brussels in 1847, where he lived in exile from 1843 until 1849. It was originally written in French as a critique of the economic and philosophical arguments of French anarchist Pierre-Joseph Proudhon set forth in his 1846 book The System of Economic Contradictions, or The Philosophy of Poverty.

(Source: Wikipedia)