He became pastor of the Protestant Reformed Church of Alsace and Lorraine (EPRAL) in 1959, then directed the Union of Evangelical Churches Chrischona (Union des Églises évangéliques Chrischona).[3] He participated in the creation of the evangelical directory, then became president of the (Fédération évangélique de France) in 1991 for a few years .[4] He founded, alongside others such as Swiss pastor and former member of the ADFI Paul Ranc, the association Vigi-sectes in 1998 who informs about religions and cults from a christian perspective.[3] He published books about religious movements, about pseudo-Christian groups he considered cults because of their supposed biblical errors,[5] and an extensive encyclopedia on Christianity. He listed 150 people who have claimed to be the Messiah from the first century CE.[6] At the end of his ministry, he became pastor of an Independent Baptist church in Moselle.[7]
In 1998, the pastor of the Reformed Church of Alsace and Lorraine Sylvain Dujancourt accused Dagon of using his anti-cult campaign to attract new people to his church.[3]
Sébastien Fath considered Dagon a "key figure of French evangelical Protestantism since the 1970s",[8] and Émile Poulat qualified him a "pioneer" in the religious issues.[9]
^Fath, Sébastien. Du ghetto au réseau: le protestantisme évangélique en France (1800–2005) (in French). Genève: Labor et Fides. p. 194. ISBN2-8309-1139-3.
^Poulat, Émile (2003). Notre laïcité publique: "La France est une République laïque" (Constitutions de 1946 et 1958) (in French). Berg International. p. 259. ISBN2-911289-65-X.