Casino, which has 110 hypermarkets in its home market, has been cutting back on super-size shops in recent years, under pressure like rivals from the rise of online alternatives and the changing habits of consumers shopping closer to home.

The group is not planning to close any of the 20 struggling stores under its "Geant" banner, the spokesman said.

Instead it could turn them into franchises, shrink their size to turn them into smaller supermarkets, or sell them to a rival retailer.

"The decisions will be taken on a case by case basis," the spokesman added.

Casino has said its Geant hypermarkets should become profitable as a whole again in 2018, a year later than it had initially flagged.

The company on Monday said it had agreed on a sale and leaseback plan for some properties of its Monoprix chain for 565 million euros ($650.20 million) as it shrinks its debts. These stood 5.4 billion euros on a net basis according to its results reported in July.

Casino shares have tumbled roughly 30 percent in 2018 on concerns about its debts and those of parent holding group Rallye.

(Reporting by Pascale Denis, writing by Sarah White, editing by David Evans)