Banks have been used to having mud slung at them over the past decade for rigging markets, ripping off customers, committing fraud, and generally flouting the law. But there is one activity that they really do not want to be associated with—complicity in war crimes.

At the end of June, however, three French non-governmental organisations (NGOs) filed a legal action against BNP Paribas, alleging that France’s largest bank was complicit in genocide, war crimes, and crimes against humanity during Rwanda’s 1994 genocide.

Neil Hodge is a freelance business journalist and photographer based in Nottingham, United Kingdom. He writes on insurance and risk management, corporate governance, internal audit, compliance, and legal...