On the Petit Pont that links the left bank of the Seine to Île de la Cité and the glories of the Notre Dame Cathedral, Clint Little, 47, from Illinois in the US midwest, was getting frustrated. “This is stupid – maybe we can see it from the back,” he suggested to his wife, Annetta, 48, and 18-year-old son, Wade.

The Littles had been thoroughly enmeshed in what is not so much a ring of steel at the heart of Paris as a suffocating lattice of metal barricades, dead ends and restricted zones, marshalled by a vast army of police, soldiers and private security officers.

Paris has never seen anything like it. The Littles certainly had seen nothing like it – and they were getting no closer to seeing the Notre Dame, which was already half covered up due to restoration works after the fire of five years ago. “In the US, we have done a lot of Olympics and there is security but we try and do it without restricting the freedom of its citizens,” Little said. His wife said: “It’s been a bit disappointing.”

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The decision to turn over the crown jewels of Paris’s attractions to the Olympic events, and the banks of the Seine to the opening ceremony, rather than parcel off the festivities to the outskirts of the city as was largely the case with London in 2012, has necessitated a different level of security for these games.

The two analogies most commonly used by locals are the restrictions imposed on Parisians during the Covid lockdown and a militarisation of the city centre not experienced since the second world war.

There are 44,000 metal barriers on the streets of the French capital, channelling people in exasperating cul-de-sacs. Access to the banks of the Seine, where about 326,000 spectators will witness athletes being carried down the river on about 80 boats on Friday evening, has been closed off to those without a QR code proving residence or some other right to be there.

The activist group, Saccage 2024, which is opposed to the games on environmental grounds, described Paris 2024 as the first ever “QR code Olympic Games” and one which could set a worrying precedent for future major events. “As many parts of the city are blocked for the Games and especially for their opening ceremony, many people and local businesses lose their most basic rights, like walking on public roads,” they said.

There is still plenty of walking being done, however, in part thanks to the closure of a confusing hotchpotch of Métro stations located closest to the glittering locations for events, including the Eiffel Tour and Place de la Concorde, necessitating a lot of head scratching and Google map searching by those trying to get around.

Traffic has been largely prohibited in a wide perimeter around the river and 30,000 police and gendarmes are being deployed on an average day over the next three weeks with it rising to 45,000 on the night of the opening ceremony. On top of that are 20,000 private security guards and 10,000 soldiers who are poised to intervene in the event of a terror attack as part of what is being called Operation Sentinelle. A huge military base has been built in Bois de Vincennes on the outskirts of Paris to accommodate them but hotels, schools and university campuses have also been taken over by the gendarmerie.

In a handwritten note to the hundreds of thousands involved in the security operation, France’s interior minister, Gérald Darmanin, wrote that “the largest global event that a country can organise” is “finally” here after four years of preparation. “Your task will not be easy,” he wrote. “I am counting on each one of you to present the most beautiful face of France, caring, friendly and professional. The eyes of the world will be set on you.”

It is not evident that the sacrifices being made by Parisians and tourists in the name of security are going down well. The cost of the security operation could well overtake that of the £1bn spent on London 2012 when the latest polls suggest that nearly 40% of French people are indifferent about the Olympics and 37% have a negative view.

On the eerily quiet streets in the “grey zone”, the area closest to the Seine, where every other cafe and souvenir outlet has shut up shop, Peter Feldmann, 66, and his wife, Roxana, 64, who own an apartment near the Île de la Cité, said they would be leaving the day before the opening ceremony for New York.

“I’ve never seen Paris so empty,” Roxana said. Her husband, who works in computation biology, added that he had struggled to understand the paperwork and rules but that “hopefully it will also confuse the enemy”, whoever that may be.

Darmanin said on Tuesday that no “specific threat” had been identified by the French intelligence service or partner foreign agencies. But while a large-scale terrorist attack coordinated from abroad is considered unlikely, there is concern over the risk of a so-called “endogenous” threat, perpetrated on command by “proxies” living in the country.

Then there are the more run of the mill flashpoints. Pro-Palestine groups have been holding daily protests outside the French Olympic Committee in northern Paris while a noisy demonstration is expected both inside and outside the Parc des Princes when Israel’s football team play Mali on Wednesday night.

Nearly a million security checks have been undertaken on those with links to the Games, and hundreds of individuals of concern have been identified and told to stay at home. Police have also raided those on their watchlists and detained a number of Islamists and far right and far left activists, the government said.

The “zero risk” approach may not be to everyone’s taste but Darmanin suggested it was paying off. “We do not have any specific threats to the Olympic Games, either from French intelligence services or partner foreign intelligence services who are assisting us,” he said.

“We’re obviously attentive to every sign, but there are no specific threats. We are, however, taking a certain number of measures, including 45,000 police and gendarmes at the opening ceremony, but also preventive measures, including administrative procedures for people we suspect to stay at home and not approach Olympic sites. I think this will pay off and allow everyone to see the most important aspects of the Games: the party and the sport.”