Workers at France's Carrefour supermarkets are striking to protest planned job cuts.

The FO and CFDT labor unions said the strike on Saturday was causing disruptions at about 300 Carrefour markets across the country. Some of the chain's biggest stores were forced to close.

The unions also are protesting a sharp drop in employees' profit-sharing bonuses, from 600 euros per worker ($740) last year to about 50 euros.

Europe's biggest retailer, Carrefour announced earlier this year that it would invest 2.8 billion euros ($3.4 billion) in online shopping over the next five years and cut 2,400 jobs. CEO Alexandre Bompard wants the investment in e-commerce to compete with Amazon.

The company also announced plans to reduce its costs by 2 billion euros by 2020.