The six-kilometre parade route led to the closure of riverside districts to most vehicles from 5:00am (03:00 GMT). Access to the high-security "grey zone" along the Seine now requires a security pass in the form of a QR code.

As the City of Light transforms ahead of the Games, temporary sports stadiums have been erected at landmarks like the Eiffel Tower, the Invalides, and Place de la Concorde. New Olympic VIP lanes have also contributed to traffic congestion.

"We're entering a very operational phase of hosting the world's biggest event," Interior Minister Gerald Darmanin said, outlining security measures. Many central Metro stations closed on Thursday and will remain shut until after the opening ceremony, which will feature 6,000-7,000 athletes sailing down the Seine on about 100 barges and boats. 

This marks the first time a Summer Olympics has opened outside the main athletics stadium, with up to 500,000 people expected to watch in person. The vast security operation, involving 45,000 officers, 1,900 foreign police, 10,000 French soldiers, and thousands of private security agents, has raised concerns.

"It's a bit like being in Planet of the Apes," Aissa Yago, a central Paris resident, told AFP. "All they need to do is throw us some peanuts." The Paris Games' concept of using the historic city center as a backdrop for sports has led to complaints and an exodus of wealthy residents.

"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 said.

Darmanin assured that French authorities are ready to welcome spectators safely, stating there is "no credible (terror) threat at this point." However, recent arrests, including a suspected far-right extremist and a man who stabbed a soldier, have heightened security concerns.

Meanwhile, athletes are arriving at the newly built Olympic Village in northern Paris. The village, showcasing innovative construction techniques, will host 14,500 people, including 9,000 athletes, at full capacity.

"The major countries are going to arrive on the first day, so Great Britain, the United States, New Zealand, Brazil, Switzerland," said Andre-Pierre Goubert, deputy head of the French delegation. The Olympics will be followed by the Paralympics from 28 August to 8 September.