Although its specific contents have yet to be released, Macron's measure would grant judges emergency powers to remove or block certain content deemed to be "fake" during sensitive election periods. It would also require greater transparency for sponsored content and permit France's media watchdog, the Conseil Supérieur de l'Audiovisuel, to combat "any attempt at destabilization" by foreign-financed media organizations.
"Thousands of propaganda accounts on social networks are spreading all over the world, in all languages, lies invented to tarnish political officials, personalities, public figures, journalists," Macron told journalists last week.
"We are going to develop our legal means of protecting democracy against fake news."
Skeptics quickly pounced. "The first question is: What is fake news? Who will define it?" said Daniel Schneidermann, a media columnist for the French newspaper Libération and the director of "Arrêt sur Images" (Freeze Frame), a leading online venue for media criticism in France.
"Fake news" has been an issue for Macron since France's 2017 presidential election, when numerous false reports claimed that he benefited from offshore accounts — stories that his far-right opponent, Marine Le Pen, regularly referenced. His campaign was also targeted in a major data breach on the last day of the contest, when thousands of emails and internal communications were dumped into the public domain before voters went to the polls.
By all accounts, his principal targets seem to be Russian state-owned media organizations, such as Sputnik and RT, formerly known as Russia Today. Both have French-language websites, and RT began broadcasting in France in late December.
At a joint news conference in May, Macron stood next to Russian President Vladimir Putin and decried these Russian news organizations as "organs of influence and propaganda that spread counterfeit truths about me." His view appears not to have changed: RT journalists, for instance, have difficulty securing accreditation for covering French government events.
"RT France journalists had already faced extreme difficulties and discrimination in doing their jobs, which included unfounded denial of access to En Marche HQ and the Élysée Palace," wrote Xenia Fedorova, chief executive of RT France, in an emailed statement. She referred to the headquarters of Macron's political party and the French presidential palace.
"Yet, recent comments by President Macron suggest that we are only at the beginning of curtailing of press freedoms in France — one that begins with an apparent attack against the 'alternative' media but may end up in persecution of all dissent, censorship and suppression of the freedom of speech for all," Fedorova added.
RT has also been the target of a crackdown in the United States, where its English-language channel was required last year to register as an agent of the Russian government in retaliation for allegedly publishing anti-American propaganda. RT's accreditation to cover Congress was subsequently revoked.
Most French journalists are loath to defend RT, and many share Macron's suspicions about the motives of organizations financed by the Kremlin. But some worry that a new regulatory law would be ineffective in fighting disinformation and would establish a risky precedent.
In an editorial, Le Monde, France's leading newspaper, said the proposal, "on a subject as crucial as the freedom of the press, is by nature dangerous."
In the French press, a common point of reference has been a similar new German law against hate speech. It was nominally intended to fight online threats, misleading accusations and defamation by forcing major social-network platforms to withhold certain comments in Germany if they are deemed illegal and offensive and have been flagged by users. Critics call it a prime example of a well-intended law gone wrong.
Since it took effect last week, a number of users — among them prominent journalists and activists — have cited cases of what they perceive as infringement on freedom of speech. The German satirical magazine Titanic, for instance, was temporarily locked out of its Twitter account. An author said Twitter removed a tweet in which she criticized German authorities for allegedly failing to pursue xenophobia investigations.
Many French journalists and academics point out that France — like Germany — already has regulations that restrict what can be published. An 1881 law, for instance, prohibits "the publication, the diffusion or the reproduction, by whatever means, of false news," among other things.
Macron's interest in social media platforms may only repeat the German example, some critics say.
"In theory, something along the lines of what Macron has proposed makes sense, but in practice it would have important difficulties," said Thomas Hochmann, a professor of law at the University of Reims and an expert on freedom-of-expression issues. "The problem on the Internet is rapidity, and it will be hard for a judge to verify very quickly which news items are fake and which are not. Besides, there is a danger that Twitter or Facebook overreact and suppress more content than fake news."
For others, even a well-intentioned law that could be seen as limiting the freedom of expression for political ends would present a dangerous precedent in a European Union where right-wing and nativist movements are on the rise.
"I'm very afraid of the bad effects that a law that has good intentions in France can have in other countries," said Frédéric Martel, a writer and broadcast journalist on France Culture, a French radio program.
"Macron is the president of France, and I believe that he's somebody in favor of freedom of expression. But we are in Europe, and we have people in Hungary and Poland looking at France," he said. "And if the French president attempts to regulate content, our model will be taken as an example for them, and they can just say they're doing what the French are doing. And of course they will do that with different intentions."
Schneidermann and others see the least risky solution to the problem of fake news as more media literacy, not regulation. This is a line many French news organizations, notably Le Monde, have also adopted, investing heavily in tools that allow readers to investigate the origins of online information sources.
"Schools have a capital role to play," he said. "That's the least bad solution."
Rick Noack in Berlin contributed to this report.