Alain Boublil, Beregovoy's chief of staff when he was finance minister in 1988, and the others are charged with using confidential information on the takeover by the state-run aluminium group Pechiney of the US packaging giant American National Can in November 1988. The defendants are accused of buying large numbers of shares in the US firm before the takeover and selling them later at a profit.
The deal is alleged to have netted 48.4 million francs ( pounds 8.9m) mostly for two businessmen with Socialist links, including one who offered Beregovoy a Fr1m interest-free loan to help pay for an apartment in Paris.
Allegations of impropriety over the loan, extended by Roger-Patrice Pelat, a friend of the Socialist President, Francois Mitterrand, were believed to have driven Beregovoy to despair. He had denied any wrongdoing over the loan and said he repaid it when Pelat died in 1989.
There were reports that he had been upset by the approach of the Pechiney trial, although he was never implicated.
Beregovoy, who served as prime minister for one year before the Socialists were routed in general elections in March, shot himself in the head on 1 May.
Mr Boublil is accused of giving the crucial tip at a lunch held to celebrate Beregovoy's 40th wedding anniversary. One of the main beneficiaries was allegedly Pelat. Charges against Pelat were dropped after he died.
The defendants face up to two years in prison and fines of up to Fr5m if convicted of insider trading - dealing in shares with the benefit of privileged information.
The trial - expected to last at least five weeks - has drawn headlines because of its links to Beregovoy's private office, and also because it is a test case for France's financial regulators, who have been criticised by some for turning a blind eye to insider deals.Reuse content