The first half of the 19th century in France was characterized by such a great shortage of cash that everybody had to use instruments of credit in order to invest, live or even take part in everyday trade. This global indebtedness led to a veritable obsession with debt, which literature was able to express in a variety of ways. The whole literary production of the time – the novels and the physiological studies of the 1820-1840s – appears in some way « fiduciarized », as the narrative does not only organize itself around the representation of the damage caused by credit, but also uses patterns and structures that belong to fiduciary logics. By studying the various ways credit fits into the narrative, we notice that literature either turns into a flat representation of credit, or shows the profound influence of the logics of credit inside the narrative. Whereas credit is a mere process of melodrama in Dumas’ or Karr’s works, it appears to be a major dynamic factor in Balzac’s novels, in which money is submitted to the complex dialectics of time and desire. Much more than a purely financial expedient, credit becomes a moral and economic way of living and interacting, and it appears to be a principle of writing.