During the early 1920s, an average of 25,000 colonial soldiers from North Africa, Senegal and Madagascar formed part of the French army of occupation in the Rhineland. The campaign against these troops, which used the racist epithet ‘black horror on the Rhine’ (schwarze Schmach am Rhein), was one of the most important propaganda efforts of the Weimar period. In black horror propaganda, images of alleged sexual violence against Rhenish women and children by African French soldiers served as metaphors for Germany’s ‘victimization’ through the Versailles Treaty. Because the campaign initially gained broad popular and official support, historians have tended to consider the black horror a successful nationalist movement bridging political divides and strengthening the German nation state. In contrast, this essay points to some of the contradictions within the campaign, which often crystallized around conflicts over the nature of effective propaganda. Extreme racist claims about the Rhineland’s alleged ‘mulattoization’ (Mulattisierung) increasingly alienated Rhinelanders and threatened to exacerbate traditional tensions between the predominantly Catholic Rhineland and the central state at a time when Germany’s western borders seemed rather precarious in the light of recent territorial losses and separatist agitation. There was a growing concern that radical strands within the black horror movement were detrimental to the cohesion of the German nation state and to Germany’s positive image abroad, and this was a major reason behind the campaign’s decline after 1921/22. The conflicts within the campaign also point to some hitherto neglected affinities between the black horror and subsequent Nazi propaganda.