Roman à thèse
A roman à thèse (French; German: tendenzroman, lit. 'thesis novel') is a novel which is didactic or which expounds a theory.
In a book on the genre and French examples thereof, Authoritarian Fictions: the Ideological Novel as a Literary Genre, literary scholar Susan Suleiman proposed the definition "a novel written in the realistic mode [...] which signals to the reader as primarily didactic in intent, seeking to demonstrate the validity of a political, philosophical, or religious doctrine."