In 1979, Calvi handled major investigations for Liberation, writing The Islamic Bomb and publishing revelations about the role played by France in a vast trafficking operation of uranium from Namibia, which was in direct violation of a UN resolution.
In 1981, Calvi published his first major paper at Grasset, "Camarade P.38," which focused on a gang of young killers of journalists in Milan during its "années de plomb."
He published revelations about arms trafficking and drug use in the Balkans (an investigation taken up by the daily La Republica that led to a documentary that aired on Antenne 2).
After leaving the Matin de Paris, he published two books on the secret services, including the OSS la guerre secrète en France pendant la seconde guerre mondiale, a book based on records declassified by the CIA, unpublished testimonies of former agents and the German secret agents responsible for tracking them.
His participation in nine films on the secret services during World War II allowed Calvi to work with Igor Barrère and Pierre Desgraupes.
Written with Marc Mazurovsky of the United States Holocaust Memorial Museum, Le festin du Reich covers the economic pillage of France by the Germans.