There is a longstanding misconception surrounding the term French noir, according to which the post-war French thriller and film noir were merely a development of, or response to, a pre-existing American tradition. This book aims to challenge this understanding of French noir, at once examining the complexity of this transatlantic exchange and refocusing debate to include a Franco-French lineage, especially in the case of French noir fiction. The result is a study of a 'genre' whose tendency is towards reflexivity and self parody. Where noir is keenly conscious of its own narrative structure, French noir is a celebration of its own French ancestry. Baudelaire is not simply a pioneer or forefather; instead, he lives on in twentieth-century French noir as a prose poetics. Sartre's Existentialism is not merely an accompanying philosophy to noir's mean streets but a crucial intertext, as relevant to the fiction and cinema of the 1990s and beyond as to the thrillers of the immediate post-war years.