Fears of some form of attack on Paris 2024 remain and have recently intensified following the ISIS-K terrorist attack on Moscow's Crocus City Hall, with France now placed on high alert following the attack, which has so far killed 145 people in the Russian capital on 22 March. The spectre of an attack has haunted all countries hosting the Games for at least 50 years.

France has suffered 22 attacks since 2015, and despite the ongoing threat, President Emmanuel Macron assured on Thursday that the open-air opening ceremony along the Seine remains the "preferred" plan, but alternatives are being considered.

Officially, all is well, and it should be, because to say otherwise would not only show weakness, but could also alarm the civilian population of Paris and cause millions of visitors to cancel their trip to the French capital to enjoy the 33rd Olympic Games.

However, uncertainty looms over the anti-drone defence shield planned for the Olympic event, which will take place in Paris from 26 July to 11 August, especially after the publication of a sensitive parliamentary report on the matter was ruled out.

"It's annoying that this is coming to light, but yes, unfortunately, contrary to the official line, things are not really working the way we would like," a senior security source confirmed to AFP, speaking on condition of anonymity.

In May 2023, during the signing of the security protocol for the Olympic Games, French Minister of the Interior and Overseas Gérald Darmanin described drones as "undoubtedly the main threat to be feared". With an estimated fleet of nearly three million drones in private hands in France, the authorities are keen to prevent these unmanned aerial vehicles from flying over Olympic sites without authorisation.

The military response during the Games was awarded to defence and security industry groups Thales and CS Group in April 2022, but the delivery of six systems, dubbed 'Parade', scheduled for June 2023, has been delayed by several months.

This delay forced the Senate to set up an information commission at the end of last year. The president of this commission, Cédric Perrin, warned defence journalists in December that the fight against drones was "not up to scratch".

Three months later, a large-scale exercise organised by the Air Force in mid-March to test the first "Parade" systems in Villacoublay, south-west of Paris, also failed to convince all participants.

In response, and for reasons of national security, the senators announced on 20 March that their report would not be made public. "This is a matter of national security" and its publication "could be dangerous".

Defence Minister Sébastien Lecornu closed the commission's closed-door hearings on 2 April, shortly before confirming that they had asked Thales for improvements to "respond precisely to all the commission's requests". Contacted by AFP, Thales declined to comment publicly.

Alain Bauer, a professor of criminology at the University of Paris, said "no system is as effective as expected", as demonstrated "almost daily by what is happening in Ukraine, although the systems are undoubtedly among the best in the world, some drones manage to slip through."

The Air Force recently purchased several "Bassalt" anti-drone systems, manufactured by Hologarde, a subsidiary of the Paris airports group (ADP), to detect and intercept drones within a 10-kilometre radius. With Bassalt, the military could "equip all the venues of the Olympic Games," including the opening ceremony, as a kind of anti-drone Plan B, according to the security source interviewed.

"It's like if you have a car that is broken or malfunctioning and you have one that is working in your garage. Which one would you take on holiday? It's clear to me," added a senior official.