• French newspaper Le Monde reported Thursday, citing France's Tracfin financial intelligence unit, that Sarkisov had bought real estate at an Alpine resort with the help of a loan from Bernard Arnault.
• The Paris prosecutor's office confirmed Friday that a preliminary investigation had been underway since 2022.
• A preliminary investigation does not necessarily imply wrongdoing.

The Paris public prosecutor's office is investigating LVMH CEO Bernard Arnault over financial transactions involving Russian oligarch Nikolai Sarkisov.

French newspaper Le Monde reported Thursday, citing France's Tracfin financial intelligence unit, that Sarkisov had bought real estate at an Alpine resort with the help of a loan from Arnault.

The Paris prosecutor's office confirmed Friday that a preliminary investigation had been underway since 2022, and that a Tracfin report "drawing the attention of the prosecutor's office to operations concerning Mr. Bernard Arnault and Mr. Sarkisov, likely to characterize acts of money laundering, has been attached to this procedure."

The prosecutor's office declined to comment further on the ongoing investigations. A preliminary investigation does not necessarily imply wrongdoing, and Le Monde cited a close associate of Arnault as saying the deal was carried out within the scope of French law.

Arnault, founder, CEO and chairman of the world's largest luxury goods company and one of the world's richest men, lost a high court case against French tax investigators in February over the legality of a 2019 raid on LVMH's headquarters. The raid related to a tax fraud probe linked to activities in Belgium.

Nikolai Sarkisov is a senior figure at his brother Sergey's Russian insurance company, RESO-Garantia.

RESO-Garantia Deputy CEO Igor Ivanov told CNBC on Friday that neither the company, nor Nikolai Sarkisov personally had been involved in the transaction, and that Sarkisov had never met Arnault.

"The transaction was managed by a small investment unit which invests professionally in European real estate. It consisted of acquiring flats in an old building in Courchevel from various private owners, with the view to sell them later to a developer once the entire building was bought out," Ivanov said in an email.

"All transactions were carried out by French companies, through French notaries by French lawyers on all sides. This was a usual real estate deal."

He added that neither the company nor Sarkisov had received any request for documents from French authorities.

LVMH this weekend sent CNBC a comment from Jacqueline Laffont, Arnault's lawyer, who said the allegations of money laundering were "as absurd as they are unfounded."

"The operation that was conducted to allow the expansion of the White Horse Hotel in Courchevel is well known and was conducted in compliance with the laws and with the support of councils. The investigation, apparently in progress, will not fail to recognize this," she said, according to the statement.

 "Moreover, who can seriously imagine that Mr. Bernard Arnault, who for the past 40 years has built France and Europe's top company would engage in money laundering to expand a hotel? I think that the senseless nature of these allegations cannot escape anyone."

— CNBC's Charlotte Reed contributed to this report.