PARIS - A Lloyd's of London insurer is offering up to 1 million euros ($1.3 million) in exchange for clues that could recover jewels worth an estimated $136 million seized in a heist in the French Riviera resort of Cannes last month.

The broad-daylight looting by a lone thief of precious jewellery on exhibition at the Carlton Hotel was France's biggest ever gem theft.

"A reward of up to 1,000,000 euros pro rata is offered to the first person who provides information which leads to recovery of the goods," SW Associates, a Paris-based loss adjuster and risk manager working for Lloyd's of London, said in a statement.

The statement, with photographs of two diamond rings, a brooch and a necklace from among the stolen pieces, will be published in Le Parisien, Nice-Matin and the International Herald Tribune newspapers on Wednesday, SW Associates Managing Director John Shaw told Reuters.

He said it was hoped the reward was enough to encourage a witness, a person close to the robbers or someone who has been approached to buy the jewels to come forward with information.

Any payout would take time. "We have to get the jewellery back first, evaluate the value of the recovered jewellery and then, once the police is satisfied we're not about to recompense the robbers, we can arrange the payment," Shaw said.

The heist took place around midday when a thief wearing a cap and scarf and armed with an automatic pistol burst into the Carlton, threatened security guards and sales staff and left moments later with a briefcase containing 72 pieces of jewellery from a collection belonging to diamond specialist Leviev.

In 2008, SW Associates offered a $1 million reward for information about a $105 million jewel heist from the Harry Winston store in Paris and recovered more than half the stolen pieces thanks to a person coming forward.

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