Three men and a woman have already been charged.
One of those men, a 37-year-old, was in a couple with the woman and they have children, Beccuau said this month.
The couple were arrested after their DNA was found in the basket lift used during the robbery.
The man’s criminal record contained 11 previous convictions, most of them for theft, she said.
The first two men arrested earlier were also known to the police for having committed thefts. Both lived in the northeastern Paris suburb of Aubervilliers.
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.
The loot has still not been found.
The audacious heist made headlines worldwide and spotlighted museum security in France, which has had a series of break-ins at cultural institutions.
France’s highest audit institution said in a cutting report this month that the Louvre had prioritised rendering the museum more attractive, including by acquiring more artworks, at the expense of security.
The museum’s director, in an appearance before lawmakers, has pledged more police and security cameras, acknowledging failings that led to the theft.
Adding to its current woes, the Louvre last week announced the temporary closure of one of its galleries because of safety concerns over a ceiling.
The closure underlined the dilapidated state of some of the structures, as well as the challenges of welcoming millions of people every year in a historic building that mostly dates back to the Renaissance era.
- Agence France-Presse
