‘The ancien regime”, as applied to 18th-century France, always sounds like such a solid proposition. It speaks of arbitrary power, stiffened with protocol, girded by gold, topped by a dusting of icing sugar (you could always spot a noble by their terrible teeth) and utterly stuck in its ways. Until, that is, revolution arrived in 1789 with a clap of thunder to reset the clock so that everything could start over. Yet, as Robert Darnton shows in this enthralling book, the last 50 years of old France were in fact febrile and shifting, rocked by a series of social and political affaires that reached far beyond elite circles, engaging men and women who were more used to worrying whether the cost of bread would rise by another two sous.

Darnton calls this new flexible mood the “revolutionary temper”, by which he doesn’t simply mean that French people eventually became so cross that they embarked on a programme of violent protest that led to the guillotining of the king and queen in 1793. Rather, by “temper” he is referring to “a frame of mind fixed by experience in a manner that is analogous to the ‘tempering’ of steel by a process of heating and cooling”. In other words, he suggests that between the end of the war of the Austrian succession in 1748 and the storming of the Bastille in 1789, the French population underwent a series of convulsions, some as molten as others were icy, which resulted in a subtle but powerful molecular shift. After 500 years of rigidity, “it made anything seem possible”.

Take the Jesuits. For well over a century they had haunted the popular imagination as a collective bogeyman, loyal only to their “general” in Rome, yet with fingers in every French pie. In 1760 the tide began to turn when commercial courts in Marseille and Paris ruled against them in a bankruptcy case. From here a special investigation found the Society of Jesus (the order’s proper name) to be gratifyingly wicked: they specialised in poisoning their enemies, were relaxed about theft, especially if the victim was rich, and, most egregious of all, their larders were found to be stuffed with “an astonishing amount of coffee”.

Ordinary Parisians picked up these notions from loose talk, pamphlets, and above all from ribald street songs. According to the progressive commentator Baron von Grimm: “A holy horror has taken hold of the common people, and one is persuaded that the Jesuits spend their lives talking to their pupils about murders, assassinations, and abominations.” It is this process by which thoughts, feelings and attitudes were gusted across the city and between individuals that is the focus of The Revolutionary Temper. Darnton refers to these bruits publiques as “an early information system” and, while he doesn’t labour the point, it’s clear that he is thinking in terms of today’s social media. Within an astonishingly swift five years, the Society of Jesus had been run out of town.

One of the main charges against the reverend fathers had always been that they seemed so cosy with the king, dripping pious poison into his ear while feathering their own well-appointed nests (along with their passion for coffee, they had been exposed as having fancy tastes in interior design). This was ironic, writes Darnton, because all the hard evidence suggests that church and crown couldn’t stand each other. Louis XV, a spectacularly promiscuous man with a string of “unsuitable” mistresses (Mme de Pompadour was a plotter while Mme du Barry had once worked in a brothel), was naturally tetchy about being on the receiving end of endless clerical finger wagging. At one point relations got so bad that there was wild talk about the Jesuits plotting to murder the priapic old man.

In the end they didn’t need to, because Louis XV died in 1774 after a 59-year reign, and the far better-behaved dauphin came to the throne. But if pious types thought that it would be plain sailing from now on, they were mistaken. Louis XVI might not have mistresses, but he did have a wife and she turned out to be more unpopular than all the previous shady ladies put together. Marie Antoinette was not only “L’Autrichienne” – France had only just finishing beating the Habsburgs on the battlefield – but she was cavalier with other people’s cash. Parisians were horrified to learn that in 1781 Her Majesty had acquired diamonds worth 750,000 livres, and that her new porcelain dinner service cost nearly a million. For comparison, a skilled worker at this time earned three livres a day, while by 1789 a loaf of bread had risen to almost a full day’s pay for most unskilled labourers. No wonder that by the height of the financial crisis ordinary Parisians took to calling her “Madame Déficit”.

There have always been queens who spend too much or sound too foreign, but the difference this time was that French men and women felt they had a better, clearer, perspective from which to pass judgment. In 1783 hot air ballooning became all the rage, with two buccaneering Frenchmen disappearing into the sky on 21 November in the equivalent of a picnic hamper. “All of Paris saw it but could hardly believe it – two men, in the air, 3,000 feet above the earth, flying!” Balloonists who followed along in their slipstream regularly tacked over national borders, including Jean-Pierre Blanchard, who in 1785 made the first cross-channel flight. If you squinted hard enough it really seemed as if you could see as far as America, a country that had recently undergone its own thrilling revolutionary reckoning and now functioned as a shining emblem for a country that increasingly saw itself in metaphorical chains. (Though, in the rush to praise the liberté, égalité and fraternité of the godly Quakers and rugged frontiersmen of the New World, French commentators overlooked the thousands of trafficked Africans in the southern states who were held in actual manacles.)

By the end of this exhilarating book, Darnton has done so much more than provide an account of France during the dying decades of the monarchy. Ever since his breakthrough book of essays, The Great Cat Massacre, in 1984 he has concentrated on combining the forward thrust of narrative, or “event”, history with due concern for the deep structures of the past. Historically, these two distinct methodologies have positioned themselves sternly in opposition to one another, but here Darnton proves that it is possible to have the best of both worlds. The result is deep, rich and enthralling, and gets us as near as we probably ever can be to that elusive thing, the collective consciousness.

• The Revolutionary Temper by Robert Darnton is published by Allen Lane (£30). To support the Guardian and the Observer buy a copy at guardianbookshop.com. Delivery charges may apply.