Mr Pineau-Valencienne, the equivalent in France to Lord Weinstock, chief executive of GEC, has since Friday been incarcerated in a Brussels jail.
The Belgian authorities yesterday arrested a second man, Valentino Foti, an Italian, in connection with the same case, which involves fraud, embezzlement, falsification of the group's accounts, and abuse of confidence. Mr Foti was the majority shareholder of PB Finance, in which Schneider once had an indirect shareholding.
Mr Pineau-Valencienne will appear in court tomorrow, when a decision will be made as to whether to hold him longer. According to French sources, the French Prime Minister, Eduourd Balladur, has called his Belgian counterpart, Jean-Luc Dehaene, to express his concern.
The French business community has also, through full-page newspaper advertisements, expressed its support for Mr Pineau-Valencienne's 'moral rigour' and deplored his treatment in Belgium.
The charges relate to complaints by minority shareholders in two Belgian Schneider subsidiaries - Cofimines and Cofibel - during a takeover bid in 1992 by Schneider's parent company, SPEP. Cofimines
and Cofibel complained the bid undervalued their shares. The case was settled out of court earlier this year after Schneider and SPEP, which have since merged, agreed to raise the offer price. The Belgian authorities, however, are still investigating. PB Finance has been repeatedly reported as having been involved in money laundering, a charge the company has always denied.
Schneider's share price rose Fr14 yesterday to Fr404.
Pierre Berge, chairman of Yves Saint-Laurent, was indicted in Paris yesterday for insider dealing over the sale of shares in the fashion and luxury goods group worth pounds 12.1m.
He is also accused of breaching a stockbrokers' monopoly on the sale of shares. The shares were sold before publication of poor YSL results in 1992.