In the preface to his story, Balzac discusses a socially instructive lesson, which is illustrated through the contrast between The Firm of Nucingen and César Birotteau. In 1840, in the preface to the first edition of the story Pierrette, he clarifies his point, emphasizing that the focus is on the contrast between the protagonists of these works—César Birotteau and Baron Nucingen.

What, then, is the meaning of this contrast? First and foremost, Balzac intends to highlight the difference in the moral character of these two capitalist figures. Birotteau’s character is conceived by the author as an “image of honesty,” whereas Nucingen, the “financial Napoleon,” openly and cynically mocks the very notion of honesty, asserting that people are honest only in appearance.