If you are on holiday in France, and want to improve your French by reading a good political thriller, then I recommend Dans L'ombre ("In The Shadows") by Edouard Philippe and Gilles Boyer, published by JC Lattès. It is written in a fluent, contemporary French; I confess I had to turn to my dictionary on about a hundred occasions during its 500 pages. M. Philippe is currently mayor of Le Havre, and thus a major local politician who also has, I guess, national ambitions. M. Boyer is the senior political adviser to Alain Juppé, the French foreign minister who was prime minister in the 1990s.

M. Boyer would call himself an "apparatchik", the one who works in the shadows. Indeed the novel is written in the voice of an apparatchik. As the narrator says of himself: ''I am an apparatchik. I have always been one. I have never thought of myself as a politician. I know many of my opposite numbers who have wished to cross the barrier. Some have succeeded quite well. There are not many of them and I don't like them... in my world, politicians and apparatchiks exist together. Neither can survive alone. All those who deceive themselves about their role are living disasters."

For a British example, one only has to turn to Sarah Helm's play Loyalty, currently at the Hampstead Theatre, London until 13 August. This "fictionalised memoir" describes the role that Tony Blair's chief of staff, "Nick", played during the Iraq war. "Nick" is also an apparatchik and he is based on Ms Helm's husband, Jonathan Powell, who undertook that role for Mr Blair. Both in this play on the London stage, and in this French novel published last month, the intimate workings of politics are explained much better than by conventional political analysis.

Dans L'ombre is set during a presidential campaign. The narrator works for the right-wing candidate, always referred to as Le Patron by his staff. His socialist opponent is the outgoing President. It promises to be a tight race. The Patron has just triumphed in a primary election conducted by his party in which voting took place on the internet. One day, however, a young staff worker, close to the Patron because of a family connection, receives an anonymous phone call: "Pinguet knows who falsified the primary election. Pinguet could tell you about it. But Pinguet is dead. Curious, no?'

The narrator reflects: ''Electoral fraud is part of the field in which the apparatchik works. He is not obliged to practise it, but he is required to understand it." More than that, in the novel at least, he must deal with the accusation in such a way that it doesn't derail the candidate's campaign. As the narrator says: "When a problem can be summed up in a simple and explosive phrase, it is at once explosive and insoluble. Complicated problems are easier to deal with."

The allegation of electoral fraud, however, was both: capable of being explained in a few, potent words, yet a tangled knot to unravel. For this reason – in a wonderful passage – the apparatchik finds he has to amend the speech that the candidate has already begun to deliver to a packed stadium at the final meeting of the campaign. The candidate is reading from an autocue. How to alter the text now that it is scrolling? Answer: wait for the speech to be interrupted by applause and then work on a computer with manic speed.

While this sort of helter-skelter is going on, the narrator reflects that paranoia is the characteristic condition of politicians and apparatchiks. "In politics you spend as much time wondering what others will do as you do in working out what you should do."

So it is impossible to be in politics for several years without becoming paranoid. Moreover, you cannot really do politics unless you have a large ego. "A politician is an ego without limits who permanently thinks that he or she is better than anyone else, and that only through him or her will problems be resolved, life be changed and peace be preserved... the natural consequence of this is an excessive swelling of the personality. Very quickly all that happens around the politician with the big ego is seen in simple, brutal terms: what doesn't work has been done against me; those who are not with me are against me: coincidences don't exist."

At the same time, Dans L'ombre describes the uplifting times in politics. The candidate visits a factory making medical imaging equipment. There he found an occasion for addressing a word to everyone present, as if he had all the time in the world. "These visits offered him the chance to touch people physically, but also morally because he shared for a moment their lives, their struggles, their worries." The unchanging techniques are reiterated. "In politics, many of the things one does have little value, but it is important to do them correctly. You have never seen anybody lose because they were mediocre, but a brilliant candidate who doesn't do exactly what is required risks being surprised when the results are read out."

Back to the big election meeting, the great occasion for true believers. Party members attend for a variety of reasons – some having risen at 5am to travel hundreds of miles by coach – but they are guided by the same faith. These meetings are like pilgrimages. They constitute a moment of intense political communion. "Only those for whom party membership represents a collective adventure can understand that." One goes to them "because one should and because finally one meets the leader of the believers and the protector of the true faith... one attends them above all because what counts much more than the destination is the journey itself... You mix with everybody, you make new friends, you learn things... in short, you become part of a community."

As for our apparatchik waiting to edit the candidate's discourse as the speech scrolls across the screen of the autocue, it was all wasted effort. For the candidate began to improvise. "The audience was captivated. It was no longer a speech to which one listened, but more like a conversation between a man and a crowd. It was a magic moment." That's politics, and a book or a play can show its texture better than anything else.

a.whittamsmith@independent.co.uk