French Prime Minister Manuel Valls warned yesterday that the country must be prepared for more deadly attacks and will have to "learn to live with the threat".
He also called on French citizens to join the reserves if they are able.
French authorities investigating the truck attack that killed 84 people at a Bastille Day celebration in Nice detained two more people Sunday and released the dead attacker's estranged wife as they tried to determine whether he had been an Islamic extremist or just a very angry man.
Following the silence, for which thousands of people flocked to the Promenade des Anglais, there was applause and a rendition of the French national anthem as many of those singing defiantly raised their fists in the air.
He was one of several calling for action, and not merely "the same old solemn declarations" from the government, as Le Figaro daily said.
"But I want to say, because it's the truth, that everything that should have been done over the last 18 months. wasn't done".
But Cazeneuve defended France's security efforts, saying the country was facing "a new kind of attack" which highlighted "the extreme difficulty of the anti-terrorism fight".
Mohamed Lahouaiej Bouhlel, the man who slammed his truck into a Bastille Day crowd in Nice, was a fast-living petty criminal who drank, did drugs and had an "unbridled" sex life up until a few months ago.
Paris prosecutor Francois Molins, who oversees terrorism investigations, said attacker Mohamed Lahouaiej Bouhlel had clearly plotted out the Bastille Day attack, with reconnaissance visits to the beach-front area where he mowed down revellers.
No evidence has established any clear link between Bouhlel and ISIS, despite the group's claim of responsibility for the killing, Molins said. French authorities said the Tunisian-born attacker was inspired by terrorist organisations.
Mr Cazeneuve said Bouhlel was "an unbalanced and very violent individual".
France imposed emergency rule after the November 13 attacks carried by Islamist militants that claimed the lives of 130 people in Paris and left scores of other wounded.
France is also home to hundreds of jihadists who have flocked to fight alongside IS.
But the Socialists have also said they will draw the line at some of the opposition's more controversial demands.
Mohamed Lahouaiej Bouhlel drove at the crowd on Thursday night, zig-zagging along the seafront Promenade des Anglais for two kilometres as a fireworks display marking the French national day ended.
A South African man who looked on in horror as he careened through the crowd on the Nice promenade, said he looked "calm".
"My wife is dead, where is my son?"