After classical studies at the Collège de Saint-Laurent, he devoted himself to studying and teaching philosophy. Lafrance pursued in-depth studies in philosophy, earning three doctoral degrees: one from the Université de Sao Paolo, Brazil (1964); a second from the Université de Louvain in Belgium (1967); and a third from the Université de Paris (1982).
In collaboration with other researchers, he published three volumes on Les Présocratiques, and two volumes on La Ligne en République VI de Platon, which were considered by experts a major 20th century contribution to Platonic studies. He also published less specialized works such as La Théorie platonicienne de la doxa (1981) and Méthode et exégèse en histoire de la philosophie (1983), which were a benefit to many students.
He taught at various universities, but it was at the University of Ottawa that he made a career for himself. Taking advantage of his 1996 retirement, he pursued research in philosophy and continued his collaboration with numerous scientific and philosophical journals. He was named professor emeritus, a title reserved for the most deserving within the university teaching body, and was a member of the Royal Society of Canada.