Where lies the Seine in Baudelaire’s Tableaux parisiens? A response to this seemingly simple question entails addressing a number of unanticipated issues if one aims to provide an accurate and complete image of the river’s place in the most referential (and most commented) section of Les Fleurs du Mal. The traps one may fall into include the intricate and problematic ties between reality and the ideal in Baudelaire’s work; the intense stratification of meaning in his poems; counterfeits and distorted specular effects that are often deceptive; exoticism; romanticism; symbolism... and the abundance of recent and less recent efforts by critics to tackle every one of these issues. Untangling these issues leads our investigation to an eminently Baudelairean paradox: the more inconspicuous the Seine is, in the eighteen poems that make up the Tableaux parisiens, the more its presence is significant and the more pronounced is its poetic role.