In a recent official report it has been revealed that Mediator a 'miracle' diet drug prescribed to French people may have killed thousands of lives.
Since its launch in 1979, Mediator was prescribed to up to five million people until it was banned last year. It was also used as an appetite-suppressing drug by thousands of healthy men and women.
However, the report by Paris government scientists said that it may be linked to the deaths of up to 2,000 people and caused heart problems in 3,500 more.
An active ingredient in Mediator, called benflourex, could have caused thickening of the heart valves, fatigue, and breathlessness - and had no effect at all on weight loss, the report said.
One French press investigations has alleged that the product owner Servier campaigned intensively to keep their highly lucrative product on the market.
Mediator was only banned after a study in April 2009 by lung specialist Dr Irene Frachon linked it to scores of patients with otherwise unexplained heart valve problems.
French Health Minister Xavier Bertrand has now vowed to launch an investigation.
"'Our message to all those who took Mediator is that they must see a doctor - particularly those who took it for three months over the past four years," the Daily Mail quoted Bertrand as saying.
President Sarkozy said last week, "The public deserves no less than total transparency in this matter."