More than 14,000 women in France were prescribed Depakine, the Sanofi drug firm's brand name for valproate, despite the potential risks to foetuses which became known in the early 1980s, and which associations representing victims say may have affected 50,000 people in the country.
The six people were volunteers in now-suspended trials for a new pharmaceutical drug performed in a laboratory in the western city of Rennes.
Jacques Servier was founder of company that made Mediator weight-loss drug which has been blamed by officials for up to 500 deaths.
Man's death came two days after medicines watchdog ANSM asked pharmacies to stop selling a batch of diuretic that may contain a sedative.
Company boss faces manslaughter probe as victims complain of compensation delays over product that may have killed more than 500 people.
Top French medics denounce pharmaceutical industry's "tricks and lies" for dodgy drugs that cost welfare system up to 10 billion euros per year.