No one does scandals quite like the French. It is not so much the who-did-what-and-to-whom that makes them gripping, but the tremors they seem to send through the whole society. And still they go on. Today you can choose between, at one end of the scale, the fascinating domestic story of little Gregory, a boy murdered in a tiny self-enclosed community in the Vosges mountains, a case which raises superstitious fears about life in la France profonde, and, at the larger, public end of things, the law’s delay and the national reluctance to face the shame of Vichy through the trials of Klaus Barbie, the pardoning of Pétain and so on.

Sarah Maza, who is Professor of History at Northwestern University in Chicago, has investigated a number of scandalous court cases in the twenty or so years before the French Revolution. The best known is the Diamond Necklace Affair, in which Marie Antoinette was implicated by two adventurers, Nicolas and Jeanne de La Mottes. The moment in this famous affair that still almost defies belief is when the La Mottes persuaded Cardinal Rohan, the Grand Almoner of France, to meet Marie Antoinette at night in the gardens of Versailles. What the Cardinal did not know was that this ‘Marie Antoinette’ was a street girl the La Mottes had disguised and coached for the purpose. They had further persuaded Rohan to buy a diamond necklace, at whose even Louis XV had balked, to give the Queen in return for supposed political advancement. The case had everything: money, crime, sex and – the biggest issue at trial – whether Rohan was guilty of lese-Majesté and criminal presumption in even thinking Marie Antoinette might be available for a nocturnal rendezvous organised by such shady types as the La Mottes.

This is an old story, but Professor Maza has had fun with it. Her contention is that the trial and the scandal were really about the influence of women and the public fear that the corrupt aristocracy – ‘feminised’ by powerful mistresses and weak kings and courtiers – had too much influence on the public ‘male’ world of political power, justice and administration. Marie-Antoinette was rumoured to have lesbian longing, and the word most often used to – – describe the necklace (‘bijoux’) was a euphemism for the female parts, used by no less a writer than Diderot in Les Bijoux Indiscrets, in which the eponymous jewels relate their adventures.

These details of the Rohan case and others that Maza examines reached a very wide public, thanks to the distribution of memoires judiciaires, highly coloured and partisan accounts of events written by the barristers involved. Such was the public interest in these trials that when even Voltaire sold no more than 3000 copies of his books, the memoires could sell as many as 10,000. Maza contends that these memoires played an important role in forming and shaping ‘public opinion’. Not only were they the most popular form of reading, but the cases they dealt with were peculiarly instructive in the social and political tensions of the period. All historians want to see such patterns and tensions (particularly just before the French Revolution), but Maza is thorough and convincing. The most fascinating part of this brilliantly argued book concerns the whole idea of how public opinion is first formed in a country that is politically mature but lacking effective means of mass communication.

One of the key figures is Beaumarchais, author of The Marriage of Figaro, social climber, irritant and author of memoires judiciaires. Imprisoned and bankrupt in 1773, Beaumarchais attempted to bribe the trial magistrate Louis Goezman, as custom and practice strangely entitled him to. Goezman and his dimwitted wife did not play it by the book, and Beaumarchais was able to get out of trouble by a series of scorching polemical memoires that accused the Goezmans of dishonesty and mocked Mme Goezman’s arriviste vulgarity. The memoires made Beaumarchais’ name as a writer. They contained scenes of firce as well as drama, much of it from the writer’s own imagination, as was becoming the fashion. Although Beaumarchais received an official rebuke and the four memoires were condemned to be burned, it is not clear – and this is my only reservation about the book’s main theme – to what extent these and other memoires were subject to the laws of libel.

Court cases, according to Maza, supplanted theatre as the most influential form of popular drama: Beaumarchais’ memoires had more impact at the time than his critically unpopular Marriage of Figaro. The crisis in the legal system precipitated by Chancellor Maupeou in 1771, as a result of which many lawyers went on strike, had two crucial effects: it made lawyers politically aware and it opened up the courts to a younger generation. It was these young lawyers, Maza argues in more detail than I can suggest here, who really formed a bridge between the great philosophes of the mid-century – Voltaire, Diderot, Rousseau – and the revolutionaries themselves. And, naturally enough, lawyers of all ages went on to form an enormous part of subsequent legislative assemblies.

This cautious, scholarly book is happily lacking in the jargon relied on by lesser academics; in fact the only minor verbal irritation is the odd lapse into journalese: Voltaire is occasionally the ‘sage of Ferney’ and Rousseau is once too often ‘the Genevan writer’. But the memorable qualities of the prose are its clarity and good humour, which can deal with knotty economic history and the simple tale of the country servant girl whose employer approached her stark-naked with obvious attentions. He had been servicing the housekeeper twice a week, but she was in love with the gardener and had to borrow the maid’s room to entertain him as well, so that when the maid felt she could no longer lend her room for this immoral purpose and then the master came on her stark-naked … well, you can imagine! But Professor Maza, through her cool examination of the trial, makes exemplary history of it, and very entertaining it is too.