France's Carrefour group said Tuesday it is overhauling its business in a transformation plan involving thousands of job cuts, a product revamp and new partnerships in China.

Carrefour, which was the world's second-biggest retailer at the start of the century after US giant Wal-Mart, has since slipped to ninth position, according to the Deloitte consultancy, having been overtaken by the likes of Amazon and Costco.

Some 2,400 jobs will be cut in Carrefour's French operations, which currently total 10,500 staff, via voluntary redundancies, the group announced.

The retailer's product mix is to be redirected towards more organic produce, with a target of increasing sales in that segment almost four-fold by 2022, it said.

It will also accelerate its online development, aiming for a 20-percent market share in French online food sales, and open at least 2,000 new neighbourhood outlets in its French home market in coming years.

Carrefour is hoping for 2 billion euros ($2.45 billion) dollars of annual savings from 2020 onwards thanks to the restructuring as it streamlines logistics and overheads.

Carrefour also said it had signed a deal with Chinese internet giant Tencent and supermarket group Yonghui which will take a minority stake in Carrefour's Chinese subsidiary.