Jailed without charge: The French have been shocked by the detention in Belgium of a dashing business hero

IT IS the stuff of which thrillers are made. The star plays a confident and successful company chairman - a patrician character respected by his peers and a frequent guest at intimate political dinners. A Harvard Business School graduate, his transatlantic savvy is tempered by that touch of French class and the bourgeois intellectualism that is the hallmark of French captains of industry.

His success in turning round a stagnating electrical group that now has a turnover of Fr56bn ( pounds 6.7bn), culminating in a bold hostile bid for an American rival - the biggest ever launched by a French company in the US - has earned him a reputation as a tough and ambitious manager.

One business magazine has crowned him Businessman of the Year, and his peers are ready to elect him head of the French version of the Institute of Directors, the Patronat.

Riding high, our hero is asked to help with a little legal inquiry concerning a couple of the group's foreign subsidiaries - some fuss about a long-past takeover battle. The situation has anyway been settled recently to everyone's satisfaction. It is now just a case of tidying up a few loose ends, a spot of local bother, nothing serious.

Knowing the buck stops at his desk, he is only to happy to help out and sets aside a day for it. He has not even packed a toothbrush. He has expected to answer a few questions and then return home. But, instead of this, he finds himself jailed on suspicion of fraud, embezzlement, falsification of annual accounts and abuse of confidence. The Kafka-esque nightmare has begun.

The attraction of such a film, of course, is that it tells a true story. The chairman of the French electrical engineering group Schneider, Didier Pineau-Valencienne has now spent a week behind bars in a Belgian prison that usually houses petty criminals and drug addicts. He has not been arrested and is innocent until proved guilty, but under Belgian law the independent juge d'instruction has the right to detain suspects while he gathers enough facts to determine whether there is a case to answer.

In France, the outrage has rekindled all the old animosities between the mighty French state and Belgium - regarded by all self-respecting Frenchmen as a joke, particularly since French businesses now control a large chunk of its industry. Liberation, the left-leaning newspaper that is rarely the preferred reading of the French business community, summed it up in a headline that read: 'Small-time Belgian judge locks away big-time French company chairman'.

Mr Pineau-Valencienne's peers took out a full-page advertisement pledging their support for him, the French ambassador to Belgium made a point of visiting him in prison, and the French prime minister Edouard Balladur has been putting heavy pressure on his Belgian counterpart, Jean-Luc Dehaene.

All in vain. The Belgian judiciary, which as many Belgian commentators have pointed out this week is independent (infering that French judges are not), decided on Wednesday that Mr Pineau-Valencienne and a one-time financial partner detained as part of the same inquiry, Valentino Foti, should be held for up to a month longer. Lawyers for both men said they would appeal the decision, and the inquiry that Mr Pineau- Valencienne confidently predicted would cause no surprises has so far knocked more than 5 per cent off the value of Schneider stock.

Not everyone is happy with this state of affairs. Mr Philippe Quarre, a practising Belgian advocat and a lecturer in judicial procedure, says that preventative detention should be used only if there is a risk to public security. He rejects the defence of the juge d'instruction, Mr Van Espen, that he needed to incarcerate the men to prevent them tampering with evidence and warns that the Belgian legal system is at risk of becoming a laughing stock.

But there is a growing sense that there must be a blazing fire to produce so much smoke. On Thursday a Franco/Belgian police team searched Schneider's Paris headquarters and Mr Pineau-Valenciennce's home, removing annotated documents relating to the group's offshore investments. Rumours abound that the net will be cast even wider next week.

The crime of which Mr Pineau-Valencienne has not yet been properly accused centres on his role as chairman - how much did he know and when did he know it? In 1992, Schneider made an offer to buy out minority interests in two of its Belgian financial subsidiaries, Cofibel and Cofimines. Minority shareholders complained that the bid deliberately undervalued the company and that Schneider had, in an act of gross mismanagement, allowed a Swiss-registered company, Fimo, to buy into the capital of PB Finance, in which Cofibel had a stake. The company no longer has any connection with PB Finance, in which the Italian financier Valentino Foti was involved, and Schneider, in an out-of-court settlement, agreed to increase its original offer to the minority shareholders. But by this time the judicial inquiry was unstoppable, fuelled by the suspicion that PB Finance has been involved in money laundering.

It is argued that Mr Pineau- Valencienne must have known both about the buy offer for Cofibel and Cofimines (of which he was president) and the shady business dealings of PB Finance. Here the case is less convincing, for Mr Pineau Valencienne has always said that he delegated that side of things to Mr Foti and Mr Jean Verdoot (who died last year). So while the Belgians pursue their investigations in France and Switzerland, Mr Pineau-Valencienne languishes in Forest prison.

The story has already been serialised at great length in both the French and Belgian press and as political thrillers go, it has all the essential ingredients: good guys, bad guys, a glamorous hero who may perhaps win in the end thanks to the unstinting efforts of a humble legal officer, say, and more than a whiff of Mob drugs money. Best of all, the spinoff potential is considerable. If The Trial does well you can expect the sequel, The Chairman's Revenge, at a cinema near you some time next year.

(Photograph omitted)