In the work of the missionary and ethnologist Francis Aupiais, the two films known as Le Dahomey chrétien et Le Dahomey religieux, made in 1930, document respectively the existence of an ancient “pagan” world and a “new” world in the process of Christianisation. Rather than concealing the interactions between two Dahomey, such a separation expresses significant aporias and syncretisms of an evangelisation process in confrontation with the vivacity of vodun cults. Through a unitary reading of the two films, the analysis of the contents of the scenes filmed by Aupiais and his operator Frédéric Gadmer intends to make a contribution to the historical and anthropological question of the “African conversion”.