EU Internal Market Commissioner Thierry Breton threatens to shut down Twitter if the short message service does not comply with European rules.
Penalties could be imposed for non-compliance, Breton told the newspapers of the Funke media group and the French newspaper "Ouest-France".
“And if the rule-breaking continues, we can shut down the platform in Europe.
No one should be fooled: we will do the same if it becomes necessary.”
The EU has been monitoring Twitter very closely since it was taken over by Elon Musk.
The Digital Markets Act and the Digital Services Act, which came into force in November and will be applied from next summer, offer powerful tools to curb the spread of lies and hatred, Breton said.
"Twitter must meet these criteria if it wants to continue to be active in the European market." There will be another conversation between him and Musk before Christmas.
Musk has declared himself a champion of freedom of speech on the occasion of his multi-billion dollar Twitter acquisition.
However, there are major legal, political and ideological differences between the corresponding ideas in the USA and Europe.
Musk's supporters have accused Twitter's leadership of censorship.
Critics, on the other hand, fear that the short message service under the Tesla boss will not take decisive action against disinformation, hate speech and fake news.
The topic of hate speech on the Internet was also on the agenda during French President Macron's visit to the USA.
After meeting new Twitter boss and tech billionaire Elon Musk, Macron wrote in a tweet on Friday that he met Musk that afternoon and had a "clear and honest discussion" with him.
Musk has committed to taking action against terrorist and violent extremist content and better protecting children online.
"Absolutely," Musk replied in a tweet in French.
Anticipation of “exciting plans”
In another tweet, Macron wrote that he also exchanged views with Musk about future green industrial projects, such as the manufacture of electric vehicles and batteries.
In addition, the President provided a photo of Musk and himself at a conference table.
"I look forward to exciting plans in France," Musk wrote in response.
He also owns the electric car company Tesla.
Macron had traveled to the United States for a state visit lasting several days.
After a pompous program in the capital Washington, he traveled on Friday to the southern US metropolis of New Orleans, which is French-influenced.
There he did, among other things, a city tour with Mayor Latoya Cantrell and met the governor of the state of Louisiana, John Bel Edwards.