Suspected mob hitman Edgardo Greco, 63, had spent the last three years working as a pizza-maker in Saint Etienne, where he had lived since 2014.
He was convicted in his absence of the murders of two brothers who were beaten to death with a metal bar in a fish shop in Calabria in 2006 as well as the attempted murder of another man.
Interpol said the killings were ‘part of a “mafia war” that marked the early 1990s’ in Italy.
His arrest reportedly came after he made the local newspaper for his pizza-making skills under his fake name in 2019.
The alias was said to be taken from an infamous gangster from Puglia, which caught the eye of Italian anti-mafia cops.
Matteo Messina Denaro was convicted of dozens of murders, including helping to mastermind, along with other Cosa Nostra bosses, a pair of 1992 bombings that killed top anti-Mafia prosecutors.
His reign of terror led the Italian state to stiffen its crackdown on the Sicilian crime syndicate.
He faces multiple life sentences that he is expected to serve in a maximum security prison and under the particularly restrictive conditions reserved for top organized crime bosses.