Armed robbers stole tens of millions of euros worth of gems in a raid on the luxury Harry Winston jewellers off the Champs-Élysées in Paris.
Three men entered the shop yesterday evening and forced staff to hand over almost all the jewels on display before making their getaway.
French media estimated the value of the haul at anywhere between €47 million and €62 million, but police said it was too early to be sure of the exact sum.
"The haul is worth several million euros. The estimates change," said a police spokesman.
Investigators believe the robbers were very well informed about their target. "Apparently they knew the names of some of the staff," the spokesman said.
The attack came almost a year to the day after another raid on the same store.
On that occasion masked robbers forced staff to empty the store's safes during a morning heist, taking at least €13 million worth of gems.