A Marseille criminal court has sentenced a Frenchman to four years in prison, fining him $103,000 and banning him permanently from working in medical services or running a company.
On Tuesday, Jean-Claude Mas, 74, the former CEO of implant-maker Poly Implant Prothese (PIP), was prosecuted after a worldwide panic in 2011, when France recommended that women with such implants should have them removed due to an abnormally high rupture rate.
Worries about the implants launched a flurry of international lawsuits and prompted calls for Europe to toughen controls on medical devices and fix its fractured oversight system.
Once the third-largest global supplier of breast implants, the company was shut in 2010 and its implants ordered off the market after inspectors pursuing a tip-off discovered vats of industrial-grade - rather than medically approved - silicone outside the PIP factory in the southern town of La-Seyne-sur-Mer.
Four other executives, including the chief financial officer, were sentenced to between one-and-a-half and three years in prison, some of it suspended, and fined.
"It's a strong signal. This decision is what victims were waiting for," said one of their lawyers, Philippe Courtois.
The president of a PIP victims group, Alexandra Blachere, called it a "symbolic sentence" that challenged any prejudice that there was "a ditzy bimbo behind every pair of silicone breasts".
The two-month trial in April and May was held in an exhibition centre to accommodate the 7,400 civil plaintiffs and 300 lawyers. Jeers from the crowd greeted Mas' appearance in the makeshift courtroom.
Health experts insist that no link has been established between PIP implants and breast cancer.
Still, women around the world with PIP implants, whether in Venezuela, France or Britain, have rushed to their surgeons to have them removed, fearing health complications.
Since France recommended removal, some 14,729 women in France - nearly half of all French women with PIP implants have chosen this option, according to French regulators.
Regulators say a quarter of PIP implants removed were found to be faulty, most having ruptured.