Abstract: In social movement studies, transnational activism is often conceived in terms of its advantages. However, transnationality can also be a complicating factor that affects protest in ambivalent or even decidedly negative ways. This article explores in detail one infamous case where the transnational nature of protest was turned from an advantage into a liability for its protagonists. At the protest march against the nuclear power plant in Creys-Malville, France on 31 July 1977, French authorities blamed demonstrators from West Germany for violence that left one innocent protester dead and three people seriously wounded. By situating this protest in a transnational chronology of French and German anti-nuclear protests, this article shows how events in West Germany did have an important effect on those in France, but also how transnationality was conflated with more fundamental problems related to the local protest mobilization.