In the new year, about half of French workers could enjoy the "right to disconnect" from work email during their off hours.

A new law, which took effect January 1, requires businesses with 50 or more employees to negotiate after-hours email rules with their employees, potentially giving them the right to ignore that late-night missive.

"Employees physically leave the office, but they do not leave their work. They remain attached by a kind of electronic leash — like a dog. The texts, the messages, the emails — they colonize the life of the individual to the point where he or she eventually breaks down," Benoit Hamon, a member of Parliament, told the BBC in May when the measure was introduced.

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There's currently no penalty in place for companies poised to violate the law. And the "50 or more employees" threshold is an important one. According to European Union statistics, a high proportion of French companies report employing only 49 people, because French workplace laws kick in at 50 or more employees. In 2015, exempt businesses (49 or fewer workers) employed 48.6 percent of the French workforce. So, this new law would potentially apply to just over half of the working population.

The benefits of going off the clock are well-document, however. A study from the University of British Columbia found people who were told to check their email only three times per day were less stressed than their always-on counterparts.

Related: In Workplace of the Future, You're On Your Own (For Better or Worse)

Could something like this ever work in the United States? Jeffrey Adelson, general counsel and managing partner at Adelson, Testan, Brundo, Novell & Jimenez, said it would be a challenge.

"At some point in time the diligent employee will feel compelled to 'catch up,' which may result in working off the clock," he told NBC News. "My experience tells me the email faucet cannot be turned off once it is on."

Lynn Taylor, a workplace expert and author of "Tame Your Terrible Office Tyrant," told NBC News that while work-life balance is a "noble cause," she doesn't see a law like this ever coming to the United States.

"Improved work-life can be accomplished in more business- and employee-friendly ways," she said. "This legislation will hurt corporate productivity because our society has come to expect instant communications and unprecedented customer service."