GENEVA — Monaco authorities have charged Russian billionaire Dmitry Rybolovlev as an accomplice in an invasion-of-privacy case that emerged from his long-running legal dispute with Swiss art dealer Yves Bouvier.

Mr Rybolovlev, owner of the AS Monaco football club, released a statement acknowledging he'd been charged by Monaco judicial authorities. They are investigating a complaint by Tania Rappo, a Bulgarian resident of Monaco involved in the art dispute, that her privacy had been invaded.

Ms Rappo says that Mr Rybolovlev's lawyer illegally taped conversations with her during the art dispute, using the lawyer's mobile phone. Mr Rybolovlev said he was confident he would be cleared of any wrongdoing.

"I have done nothing illegal," Mr Rybolovlev said in the statement. "All my actions in this matter have had only one purpose — to uncover a massive fraud in the art market."

Mr Rybolovlev has accused Mr Bouvier of overcharging him by as much as US$1 billion (S$1.36 billion) for works of art he bought over a decade. Mr Bouvier, who runs tax-free port storage facilities in Geneva, Luxembourg and Singapore, denies he engaged in any wrongdoing.

Mr Bouvier in turn has alleged that Mr Rybolovlev's lawyer, Tetiana Bersheda, bribed Monaco officials before Mr Bouvier was arrested in February 2015 when the art dispute first began. Switzerland and Monaco authorities are investigating Mr Bersheda over that claim.

Last month, Monaco's justice minister, Philippe Narmino, took early retirement after friendly text messages from early 2015 among Mr Bersheda, Mr Narmino and Monaco officials were found on the Mr Bersheda phone that the Monaco prosecutors had requested. They've all denied wrongdoing.

"I welcome this charge, which seems to me to be perfectly justified," said Frank Michel, Bouvier's Monaco lawyer.

Mr Rybolovlev made most of his US$10 billion fortune in Russia from the sale of potash producer Uralkali OJSC. In 2011, he bought Monaco's football club. BLOOMBERG