One of the European Union's top lawmakers has warned Musk over his takeover of the social networking site.
Musk offered to buy it for $44 billion on Monday. The billionaire has publicly stated his interest in buying the social media platform is based on his idea of free speech.
Musk has previously described himself as a "free speech absolutist" and his comments have left staff and others wondering if he will relax the platform's rules on what content is allowed to stay up.
In comments to The Financial Times, the EU commissioner for the internal market warned Musk against getting too strict with content moderation.
He wanted to give Musk a reality check on his plans for more relaxed content.
Everyone is welcome. We are open but not always. We know what to say to Elon. You are welcome, but these are the rules. It isn't your rules which will apply here, according to Breton.
The Digital Services Act, a new package of EU legislation that passed Saturday, brought in stricter laws on how tech giants moderate content on their platforms.
He said that the board will have to comply with Europe's laws on moderation, transparency, and hate speech.
The EU could fine the company up to 4% of its annual revenue or even ban it from operating in Europe if it fails to comply.
The DSA contains legislation that will force tech companies to open up their algorithms for oversight, as well as stipulating how companies police illegal and harmful content.
In the month before he bought the company, Musk said that it would be public for scrutiny.
Any company that operates in Europe needs to comply with our rules regardless of their shareholding, according to Breton.
Mr Musk knows this. He will quickly adapt to the Digital Services Act because he is familiar with European rules on automotive.