 He was President of the Association of Congolese Students in France from December 1968 to December 1970, and he was President of the Federation of African Students in France from December 1971 to December 1972.He practiced as a lawyer in Brazzaville from February 1976 to June 1991.At the 1987 French trial of Klaus Barbie, a German war criminal of World War II, Mbemba was an assistant defense lawyer in the team headed by Jacques Verges.