A top European Union official gave Elon Musk a warning about regulation after the tech tycoon completed his $44 billion takeover of Twitter. “The bird is freed,” Musk tweeted on Thursday night after the deal was concluded. On Friday Thierry Breton, the the EU’s internal market commissioner, replied to Musk’s message with his own tweet: “In Europe, the bird will fly by our rules.” He signed off his tweet with the hashtag #DSA—a reference to the Digital Services Act, a new piece of EU legislation to regulate social media across the continent. Earlier on Thursday, Musk tweeted out a message addressed to Twitter advertisers saying that the platform must always adhere “to the laws of the land.”