Five former managers from defunct firm Poly Implant Prothese (PIP) are on trial in southern France on aggravated fraud charges, including the firm's 74-year-old founder Jean-Claude Mas -- dubbed "the sorcerer's apprentice of implants" by prosecutors.
The scandal first emerged in 2010 after doctors noticed abnormally high rupture rates in PIP implants. It gathered steam worldwide in 2011, with some 300,000 women in 65 countries believed to have received the faulty implants.
Prosecutors have called for sentences of between six months and four years in prison for the accused.
They have also urged the court to impose a 100,000 euro ($137,000) fine on Mas and ban him from working in medical services or from running a company.
During a month-long trial in Marseille in April, the defendants admitted to using the industrial-grade silicone but Mas, who has spent eight months in pre-trial detention, denied the company's implants posed any health risks.
More than 7,500 women have reported ruptures in the implants and in France alone 15,000 have had the PIP implants replaced.
But health officials in various countries have said they are not toxic and do not increase the risk of breast cancer.
The court will not rule on the question of whether the implants pose a risk, only whether the five managers defrauded their clients and German safety standards firm TUV, which approved the implants for market.
More than 7,000 women have declared themselves civil plaintiffs in the case and hundreds packed the court during the trial in April, which was moved to the Marseille convention centre.
The others on trial are PIP's former general manager Claude Couty, quality control director Hannelore Font, production director Loic Gossart and research director Thierry Brinon.
Mas, a one-time travelling salesman who got his start in the medical business by selling pharmaceuticals, founded PIP in 1991 to take advantage of the booming market for cosmetic implants.
He built the company into the third-largest global supplier of implants, but came under the spotlight when plastic surgeons began reporting an unusual number of ruptures in his products.
Health authorities later discovered he was saving millions of euros by using industrial-grade gel in 75 percent of the implants. PIP's implants were banned and the company eventually liquidated.
PIP had exported more than 80 percent of its implants, with about half going to Latin America, about a third to other countries in western Europe, about 10 percent to eastern Europe and the rest to the Middle East and Asia.
Some of the defendants, including Mas, have also been charged in separate and ongoing manslaughter and financial fraud investigations into the scandal.
The manslaughter probe is related to the suspicious 2010 death from cancer of a woman who was fitted with the implants.
TUV was last month found liable in the case, with a court in the French city of Toulon ruling that the German firm had "neglected its duties" by failing to properly verify the implants.
The company was ordered to pay more than 50 million euros in compensation to six distributors and to more than 1,600 women fitted with the implants.