People from around the globe thronged out of packed metro trains into a southern Paris convention centre, crammed with stands in blaring colours showing off the latest innovations from startups, tech giants and more traditional firms.

The top attraction on the opening day of one of Europe's largest tech fairs will be Nvidia chief executive Jensen Huang, looking to make a mark in Europe for the company that builds the most computing hardware for artificial intelligence.

Vivatech regular President Emmanuel Macron will also attend, with a walking tour and chats with French tech startups on the agenda.

Tech watchers expect more products than ever embedding AI into everyday life to be touted in the exhibition halls over the show's four days.

"What's changed from previous years is that we've moved from AI as science fiction to applied AI," Vivatech managing director Francois Bitouzet told AFP ahead of the opening.

He trailed around 30 sectors with concrete AI-powered products on show, from luxury to insurance, health, energy, cars, logistics and more.

Around 14,000 startups and more than 3,000 investors were expected in Paris, while organisers forecast total visitor numbers to at least equal last year's 165,000 people.

- Nvidia headlining -

Nvidia's Huang -- likely sporting his trademark leather jacket -- has top billing with an opening presentation slated to last more than an hour.

Bitouzet said it was a "source of pride" to bring aboard semiconductor heavyweight Nvidia, whose high-powered GPUs (graphics processing units) are widely used to power the latest generative AI models.

"It proves that the European market in general and the French market in particular are attractive and that today (Nvidia) has ambitions for this market," the Vivatech boss added.

Cedric Foray, head of European tech at EY consulting firm, predicted that "there will definitely be announcements targeted at Europe" from Nvidia.

French digital affairs minister Clara Chappaz said France would "continue to do all we can to make the country the best place in the world to start and develop businesses and build the technology we need".

But she acknowledged that AI in particular "has never been as political as it is today".

US-based Nvidia has seen export restrictions slapped on its top-performing chips by Washington, with American politicians leery of ceding their country's lead in generative AI.

Remaining high-tech controls on China are at issue in high-stakes trade talks with Beijing.

Huang has warned that the US' superpower rival is nevertheless making swift strides to catch up.

There was little sign of impact from export restrictions on Nvidia's chip sales in its May earnings release.

But the company has warned the braking effect may be larger in the current quarter.

- Tech sovereignty -

US politics preoccupies many European tech leaders and policymakers too.

Concerns range from Trump's mercurial tariff policy to the continent's ability to stand on its own without US giants -- and the massive gap in funding for AI development between the two sides of the Atlantic.

"Sovereignty, which wasn't as important in the conversation just a year or two years ago, has become an absolutely strategic priority," Bitouzet said.

Macron is expected to again emphasise "European technological sovereignty", the Elysee said.

Such remarks from the president would build on his hyping of French and European openness to AI at a Paris global summit in February.

Top French firms at Vivatech -- where around half the exhibitors are local companies -- will include Mistral AI, a French competitor to much-bigger OpenAI.

Mistral's founder Arthur Mensch is set to discuss AI with Macron and Huang at a roundtable at the end of the first day of the event.

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NVIDIA