French President Emmanuel Macron promised to fight fake news, and he plans to do it this week — with a law.

Trouble is, Macron may soon learn, like a lot of other world leaders, that putting the fake-news genie back into the bottle is far from easy to do.

Himself a victim of a disinformation campaign during the 2017 French vote, Macron's bill "to fight fake news" will be presented in parliament on Thursday and will seek to shield elections in France from the influence of fabricated rumors, whether by extremists groups or so-called alternative media like Russia Today. Social media savvy observers, however, say archaic tools like those proposed in Macron's bill are ill-suited to stop the rapid spread of false information in the age of Twitter and Facebook.

"They're fighting tomorrow's disinformation with yesterday's tools," said Alexandre Alaphilippe, executive director at EU DisinfoLab, a Brussels-based not-for-profit organization that researches disinformation on social media and gets financing from the Open Society Foundations and Twitter. "The core issues are the mechanisms of disinformation-spreading and influence-meddling. As long as this can't be tackled, the legal fight is tenuous."

If it passes into law, online banners would warn users when information on social media is sponsored, and a judge could block access or delete it. Macron is keen to get the law enacted before the European Parliament vote next year because his government sees a mounting fake-news campaign potentially hurting the electoral process, a French official close to the president said.

Fake news has been on the minds of leaders around the world, roiling electoral processes from the U.S. 2016 presidential race to the U.K.'s Brexit referendum and Italy's March legislative vote.

Macron's own brush with fake news came in May 2017, with a volley of reports flying through social media channels alleging he had secret offshore bank accounts. A few days later as the campaign entered a "blackout" period, Macron's was left with no way to counter the flood of false information.

Standing next to Vladimir Putin in Versailles' Palace a few months later, the French president said Russia Today and its sister company Sputnik worked "as agencies of influence and propaganda, lying propaganda" that spread "misleading information" about him during the presidential campaign.

Russia Today dismissed the charges as contributing to an "environment of baseless speculation."

Macron's bill seeks to get judges and the media sector's regulator involved in the fight against fake news. A fact-checking state-run website would be created and social media would have to pitch in by warning users when a post is sponsored — or when someone pays to give it better visibility in a feed.

The tools appear "modest," said Nathalie Mallet-Poujol, a member of the Montpellier University law faculty and a director of research at French public laboratory CNRS.

"There's just no miracle solution the state could adopt," Mallet-Poujol said. "I don't think the answer can be only legal. It has to be part of an ensemble," which also includes promoting ethics, more educated citizens and more responsible platforms, she said.