He attempted to evangelise the local Arab population and he built nearly 60 new churches in Algeria.

[1] Dupuch was ordained as a priest by the Roman Catholic Archdiocese of Bordeaux in 1825.

[2] Dupuch's views on evangelisation clashed with official doctrine of the French Army under Governor-General Thomas Robert Bugeaud, who feared the Arabs might feel disrespected and rebel.

[2] He also clashed with Emily de Vialar and expelled her Sisters of St. Joseph of the Apparition from Algeria; the order focused on evangelising Tunisia instead.

By 1846, he had paid for the construction of 60 new churches, chapels and oratories in French Algeria, out of his own pocket.