The French government plans to make wearing a mask compulsory in the vast majority of workplaces to try to stop a resurgence of the COVID-19 pandemic.
The labour ministry said the new arrangement would apply to all shared spaces in offices and factories, but would not extend to individual offices where only one employee is present.
The ministry, in a statement, did not say when the new rules would take effect. It said that working from home would remain its recommended option for employees.
France imposed some of Europe's toughest lockdown restrictions earlier this year, greatly reducing the rate of coronavirus infections. But in the past few weeks the numbers of new COVID-19 cases have climbed, and public health officials have warned that contagion could spin out of control.
The government has been under pressure from trade unions to step up protective measures in time for September, when people return to work after long summer holidays, and when children are due back at school.
"The best thing we can do to prepare for the return from vacations is to reassure employees that, together, we are taking the precautions to avoid spreading the virus," Elisabeth Borne, the labour minister, was quoted as saying by the ministry.
