The companies' legal action comes with both Casino and Rallye having been targeted by hedge funds betting on their shares falling further in future due to concerns over debts and the companies' financial positions.

"For several months now, Rallye and Casino have been the subject of violent attacks and misinformation campaigns orchestrated notably by hedge funds in order to artificially reduce the value of their shares and destabilise the companies, their employees and shareholders," the two companies said in a joint statement.

"As a result, Rallye and Casino announce that they have filed a criminal complaint versus 'X' with the financial Public Prosecutor for price manipulation, dissemination of false or misleading information, and insider trading," they added.

(Reporting by Sudip Kar-Gupta; Editing by Dominique Vidalon)