French security forces began locking down large parts of central Paris on Thursday ahead of the hugely complex Olympics opening ceremony next week on the river Seine.

The opening parade along six kilometres (four miles) of the river led to the closure of riverside central districts to most vehicles from 5:00 am (0300 GMT) on Thursday.

Anyone wanting to enter the highest-security "grey zone" along both banks of the Seine, such as residents or tourists with hotel reservations in the area, will need a security pass in the form of a QR code.

The City of Light is transforming ahead of the July 26-August 11 Olympics when around 10 million spectators are expected

Temporary sports stadiums have sprung up at popular locations such as the Eiffel Tower, the Invalides or the Place de la Concorde, while new Olympic VIP lanes are the latest traffic-snarling addition.

"It's true that our concept of having a large number of temporary sites in the heart of the city, obviously with that, there are constraints, but I feel like people are seeing what we're doing," Paris 2024 director general Etienne Thobois told AFP last month.

Many central Metro stations will also be closed on Thursday until the day after the opening ceremony, which will see 6,000-7,000 athletes sail down the Seine on around a hundred barges and river boats.

It will be the first time a Summer Olympics has opened outside the main athletics stadium, with up to 500,000 people set to watch in person from stands, on the river banks and from the overlooking apartments.

Village opens

The vast security operation has been giving senior police officers cold sweats ever since it was announced in 2021 because of the difficulty of securing so many spectators in such a large, densely packed urban area.

Around 45,000 officers are set to be on duty for the July 26 parade, assisted by thousands of soldiers and private security agents.

On Wednesday, police in eastern France announced they had arrested a suspected far-right extremist who had made threats against the Games in a group on the Telegram phone application.

The installation of tens of thousands of metal security barriers all along the opening ceremony route in Paris has outraged some residents, who feel closed in.

"It's a bit like being in Planet of the Apes," Aissa Yago, who lives on the Ile Saint Louis in central Paris, told AFP this week from behind a barrier. "All they need to do is throw us some peanuts."

Elsewhere on Thursday, the first athletes are set to arrive to take up residence in the newly built Olympic Village in a northern suburb of the capital.

Comprising around 40 different low-rise housing blocs, the complex has been built as a showcase of innovative construction techniques using low-carbon concrete, water recycling and reclaimed building materials.

It was intended to be free of air-conditioning, although Olympic delegations have ordered around 2,500 portable cooling units for their athletes out of fear of the impact of high temperatures on their performances.

"The major countries are going to arrive on the first day ... so Great Britain, the United States, New Zealand, Brazil, Switzerland," the deputy head of the French delegation, Andre-Pierre Goubert, told AFP.

At full capacity, the village will host 14,500 people including 9,000 athletes.

The Olympics will be followed by the Paralympics from August 28-September 8.