He came to Paris to study philosophy at the Sorbonne but spent most of his time finishing his novel. It told a story of a rebellious 14-old boy in a Jesuit school, and his passionate love affair with a 26-year old nun. Despite the controversial subject matter, the book was published by Robert Laffont in 1950. It was well received in the UK ("The False Start", 1951) and the U.S. ("Awakening", 1952) where it sold 800,000 copies. Rossi then wrote the novella "Faces of Love and Hatred", published in October 1950. He followed that by translating fiction from English to French, including several Hopalong Cassidy Westerns and works by J. D. Salinger – "The Catcher in the Rye" in 1953, and "Nine Stories" in 1961. In need to generate steady income, Rossi began working in advertising agencies, first as a writer, and then managing campaigns for Air France, Max Factor, and Formica. Rossi also had long-time interest in cinema, and producer Pierre Braunberger offered him to make a film based on a Maupassant story. Rossi replied that he preferred creating his own stories, and wrote and directed two short films: "La machine à parler d’amour" (1961) and "L’idée fixe" (1962).