After he left Sorbonne where he was a student, he completed his studies in various parts of the world, such as Rome, Geneva, Salamanca, and Montreal.
Cohen also observes that Paris is described on the jacket of Genocide in Satellite Croatia, 1941–1945 (1961) as "a French historian from a Catholic family".
[3] The journalist Richard West days that Paris was one of a group of "anti-Catholic polemicists" who used events in the Independent State of Croatia[4] to attack the Catholic Church as a whole.
It was subsequently reprinted by a Protestant publisher in the United States as Convert or Die..., with a "blood-red cover showing a man kneeling at gunpoint in front of a priest".
West said that "In spite of this lurid presentation, Paris's book is based on careful research, much of it from Magnum Crimen.