On the day of the heist, the suspects arrived at 09:30 (07:30 GMT), just after the museum opened to visitors.
The suspects arrived with a stolen vehicle-mounted mechanical lift to gain access to the Galerie d’Apollon (Gallery of Apollo) via a balcony close to the River Seine. The men used a disc cutter to crack open display cases housing the jewellery.
Prosecutors said the thieves were inside for four minutes and made their escape on two scooters waiting outside at 09:38, before switching to cars.
One of the stolen items – a crown – was dropped during the escape. The other seven jewels have not been found.
The fear is that they have already been spirited abroad, though the prosecutor in charge of the case has said she is still hopeful they can be retrieved intact.
Those arrested over the heist that shocked France were all petty criminals rather than organised crime professionals, Paris’s prosecutor has said.
Since the incident, security measures have been tightened around France’s cultural institutions.
The Louvre has even transferred some of its most precious jewels to the Bank of France.