To secure this expansive and high-risk venue, approximately 45,000 police and paramilitary officers will be deployed, accompanied by 10,000 soldiers and 20,000 private security guards. The area to be secured stretches over six kilometers (four miles) along the Seine, accommodating around 300,000 ticketed spectators and numerous residents and tourists in surrounding buildings.

A no-fly zone will be established 150 kilometers around Paris starting one hour before the 19:30 CEST (18:30 GMT) ceremony, grounding or diverting all aviation at one of Europe's busiest airport hubs.

"This opening ceremony is the most extraordinary thing a country can do," Interior Minister Gerald Darmanin told BFM television. He acknowledged the challenge posed by the current geopolitical climate, stating, "In the current context of geopolitics and terrorism, it's an enormous challenge."

The security measures reflect the complexities of protecting an open-air event on a major river. Police snipers will be stationed on high points along the route, scanning for potential threats. Navy boats equipped with divers and sonar will inspect the Seine for explosives or infiltration attempts, and all boats in the parade will undergo thorough screening by sniffer dogs and bomb disposal experts.

River traffic will be halted, with barriers and deployable nets in place to secure the waterway. The initial plan to host up to a million spectators along the river has been scaled back, a move reflecting increased security concerns.

French criminologist Alain Bauer previously described the Seine-based opening ceremony as "criminal madness," given the heightened risks. "The risks have not changed and have become worse because of the war in Ukraine, the situation in Israel and Gaza as well as social, environmental, and political tensions in France," Bauer said.

Since last week, central Paris has been fortified with metal barriers, restricting access to residents and those with hotel bookings. The French army will oversee anti-drone operations using advanced electronic warfare technology, with drones and AI-enhanced cameras deployed to monitor the crowds.

France, which has faced numerous Islamist terror threats in recent years, including attacks on Charlie Hebdo and the Bataclan, is on high alert. "Drones are now a real risk and that's why measures have been taken," said Jean-Michel Fauvergue, former head of the police commando unit RAID. He recalled the successful security management during Euro 2016 despite high threats.

The global context, including conflicts and recent terror threats, has intensified security efforts. "If you look at the history of Islamist terror attacks, you see that every time there is tension or a foreign war, there are consequences in our country," said Frederic Pechenard, former head of French police. With these extensive measures in place, Paris aims to ensure a safe and memorable start to the 2024 Olympics.