Billionaire Elon Musk swept into Paris on Friday to hold court at an event with thousands of spectators hours after meeting the leaders of Italy and France, as European capitals jostle for investment from his electric car firm Tesla.

He told the audience at the huge VivaTech trade fair his ambition was to put neurone implants in a human brain this year and defended his controversial decision not to censor Twitter.

The maverick tech titan took to the stage to shouts of "we love you Elon", defended his record since he bought Twitter and repeated his warnings that artificial intelligence could go terribly wrong.

"My strong recommendation is to have some strong regulation for AI," he said, without specifying.

On Thursday he met Italian Prime Minister Giorgia Meloni, who tweeted later that their talks had been "fruitful" and they had discussed "innovation and opportunities".

A day later he was talking to French President Macron, who had earlier promised to "tout the attractiveness of France and Europe" as an investment destination.

Musk and Macron met a month ago and afterwards the maverick boss of SpaceX and brain implant firm Neuralink said he was considering big investments in France.

The country's technology minister Jean-Noel Barrot fuelled speculation earlier this week by telling US broadcaster CNBC that "a lot of effort and energy" had been expended to secure a Tesla factory for France.

But reports from Spain say Tesla is planning to build a factory there and Italy now appears to be waging a charm offensive.

The electric carmaker's European footprint is relatively small, having opened its first manufacturing plant in Germany last year.

- Awkward interviewee -

Europe's leaders and plutocrats are desperate to get some face time with Musk -- in Paris he had lunch with French magnate Bernard Arnault, with whom he regularly trades the title of "world's richest man".

But despite the breadth of Musk's business empire, it is his acquisition of social media network Twitter that continues to fascinate and baffle observers.

He bought the platform for $44 billion, sacked much of its staff, allowed right-wing conspiracy theorists to return and introduced all sorts of fees and charges.

Advertisers fled the platform and he has admitted the firm is no longer worth anywhere near the amount he paid.

But he told interviewer Maurice Levy, founder of VivaTech, that he was moving Twitter in a "good direction" and claimed to have got rid of 90 percent of "bots and scams" and similar things and 95 percent of child-exploitation material.

"Almost all the advertisers have come back or said they'll come back," he said.

"I feel optimistic about the future."

Musk is a notoriously tricky interviewee, prone to lengthy pauses, off-topic rambles and making coded references to sex and drugs.

On the stage in Paris, he opened with customary giggles and jokes and when asked what the secret to his drive was, he replied "crystal meth", before quickly adding that he was joking.