The last suspected member of the gang was arrested on Tuesday (local time) at a construction site in the western French town of Laval, according to a source close to the case.
The four suspects believed to have carried out the robbery have now been arrested and charged with organised theft and criminal conspiracy.
The stolen jewellery is still missing, as well as those who ordered the theft.
Crown jewels
The investigation is continuing to determine the precise role of each member of the gang, “as well as to clarify the conditions under which the theft was planned and carried out”, Beccuau said.
The thieves parked a truck with an extendable ladder below the museum’s Apollo Gallery housing the French crown jewels, clambered up, broke a window and used angle grinders to cut into glass display booths containing the treasures.
The other suspects already behind bars – men aged 35, 37 and 39 – are suspected of having been part of the four-person team.
Two of them are believed to have entered the Apollo Gallery, while the other two – including the one charged on Friday – remained outside before the group fled together.
Beccuau said in early November that the suspects were believed to be small-time criminals and not members of organised crime groups.
Earlier this week French daily Le Parisien reported one of the suspects said the gang had been hired by two men “with Slavic accents” who allegedly offered them a contract for a routine burglary.
The suspect claims he thought he was robbing a business office, the newspaper said.
The thieves dropped a diamond- and emerald-studded crown that once belonged to Empress Eugenie, the wife of Napoleon III, as they escaped.
But they made off with eight other items of jewellery, including an emerald-and-diamond necklace that Napoleon I gave his second wife, Empress Marie-Louise.
A 38-year-old woman who is the partner of one of the men is suspected of complicity. They have children together. The woman has been released on bail.
Louvre director Laurence des Cars last week promised more police and security cameras to prevent future thefts. She said around 20 “emergency” measures would be introduced, including officers being based “inside the Louvre” and 100 new security cameras around the museum.
– Agence France-Presse