In 2013 Richard was already placed under investigation concerning the alleged abuse of influence regarding the award of 403 million euros ($449 million) to tycoon Bernard Tapie in 2008, when Richard was head of cabinet of the finance minister, Christine Lagarde, now head of the International Monetary Fund.

Investigators are trying to determine whether Tapie's political connections played a role in the government's decision to resort to arbitration to settle the dispute with the now defunct state-owned bank Credit Lyonnais and which resulted with a large pay-out to Tapie.

Under French law magistrates place a person under formal investigation when they believe there are indications of wrongdoing, but that does not always lead to a trial.

"Stephane Richard firmly denies all the allegations," a spokeswoman for the Orange boss said in an e-mailed statement.

"Also, this affair does not concern Orange, therefore it has no consequences on the operations of our group," she said, adding that Richard re-affirmed his commitment to the French telecoms group and the success of his mission at its helm.

Lagarde was investigated in August last year for alleged "negligence" regarding her role in the matter. The case has not been closed yet.

Richard's lawyer said in an e-mailed statement that the new round of investigation of his client was procedural and there was no new element or fact that stood against him.

(Reporting by Jean-Baptiste Vey and Noelle Mennella, writing by Astrid Wendlandt; editing by Mark John and Greg Mahlich)