Casino, headed and controlled by veteran entrepreneur Jean-Charles Naouri and owner of the Franprix and Monoprix chains, has been plagued for years by hefty debt, declining revenues and loss of market share in an increasingly competitive domestic market.

The group, which employs 208,000 people worldwide and is France's sixth biggest food retailer by market share, has been selling assets to try to fix its finances, strained by debt taken on as a result of acquisitions. It had consolidated net debt of 6.4 billion euros at the end of last year.

It faces 3 billion euros of debt repayments in the next two years, and the holding company through which Naouri controls it is also heavily indebted.

Casino has requested the opening of a conciliation procedure, one of the sources said on Wednesday, meaning it is looking to start talks with creditors, which include major French banks BNP Paribas and Credit Agricole as well as international hedge funds, under court supervision.

The creditors had until 1500 GMT on Tuesday to give their consent to begin the process, which would then be launched officially by a French court that would also say how long the talks would last and appoint officials to oversee them.

Marc Senechal, a French lawyer, and Aurelia Perdereau, a court administrator, are seen as potential mediators to oversee the talks, the sources said.

The process is designed to reach an agreement on Casino's debt but also on how two proposed tie-up offers for the group - one from billionaire Daniel Kretinsky and the other from smaller retailer Teract - could affect the situation.

Kretinsky, Casino's second-biggest shareholder, has offered to take control of Casino through a 1.1 billion-euro capital increase. He has made his offer subject to a "substantial" reduction in gross unsecured debt through buybacks and conversion into equity of Casino bonds.

Earlier this month, Standard & Poor's cut its rating on Casino, adding further pressure on the company, whose shares are down by over 30% so far in 2023, having fallen 58% in 2022.

"We believe the consent solicitation process, combined with the group's weak operating performance, fragile liquidity position and unsustainable capital structure make a default, distressed exchange or redemption appear inevitable within six months," it said.

Casino shares were suspended on May 23, pending the release of a statement. They closed at 6.76 euros on May 22.

(Reporting by Dominique Vidalon; Editing by Silvia Aloisi and Conor Humphries)

By Dominique Vidalon