A judicial official said on Saturday that the three were jailed and put under investigation for organized armed robbery with threats and voluntary violence with arms in a group, among other charges.
The official wasn't authorized to speak publicly and couldn't be named.
Two alleged accomplices escaped after the Wednesday evening heist. Authorities have said they recovered all the stolen merchandise, which had an estimated value of about 4.5 million euros ($5.4 million).
According to police accounts, the three entered a service door, smashed jewelry stands with axes and threw bags of items out a window to accomplices who fled in a car and on a scooter.
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