French police probing a record heist at Harry Winston jewellers in Paris have arrested 25 people and recovered some of the €85 million worth of precious stones, according to a police source.

The arrests were made in the Paris region after police learned that a suspected fence who had come to France from abroad was about to try to sell the stolen jewels, the source said.

Police sources said the suspects, who included two women, were aged 22 to 67. Two caches stuffed with bank notes were discovered during the operation, one containing a million euro and the other €250,000.

A record million-dollar (€700,000) reward had been offered for helping to trace the jewels stolen in the heist at the chic jewellers in December, the biggest theft ever in any category in France.

A gang of four thieves - two of them disguised as women - stole nearly all the jewels on display at the Harry Winston boutique just off the Champs-Elysees avenue, which attracts a wealthy international clientele.

Police said at the time they were dealing with "major pros" who had meticulously planned their crime and knew the boutique's lay-out well, suggesting it may have been an inside job.

Although the robbers spoke French it was with east European accents, police said, though they said the men could have been working for anyone, including French gang bosses.

Investigators were also re-examining an unsolved raid on the same shop a year earlier in which jewels worth nearly €20 million were taken, to see if there were any possible links.