The number of strikers at EDF and Engie's electricity and gas workers (IEG), who are protesting against the government's pension reform bill, exceeded 40% at midday on Thursday.

At EDF, mobilization had reached 44.5%, the utility said.

According to data from EDF and grid operator RTE, the mobilization led to a drop in electricity production in France of around 7.8 gigawatts (GW), representing around 12% of total electricity supply.

At Engie, the rate of strikers reached 40% for all electricity and gas industry personnel - which represents a good half of the group's total workforce - and around 7% for other perimeters in France, said a spokesperson.

"Engie does not anticipate any consequences for its customers," the spokesman added.

The CFDT had previously indicated that the strike rate among all IEG personnel was over 50%.

"There is a very strong mobilization with more than 50% on the entire IEG perimeter at midday, with activity stoppages but no desire to block or degrade at the moment," José Belo, CFDT coordinator for the Engie group, told Reuters.

(Benjamin Mallet reports, written by Blandine Hénault, edited by Kate Entringer)