The scheme allowed foreign investors to quickly buy and sell shares around the dividend payment date so tax authorities could not identify the true owner.
A German lawyer has been jailed for eight years for his role in a large-scale tax evasion scandal.
Hanno Berger was accused of being the mastermind of the "Cum-ex" scheme that deprived the German state of billions in tax revenues.
Prosecutors claimed that between 2007 and 2011, Berger had helped investment bankers swap shares to collect multiple reimbursements for taxes that they had only paid once.
The state court in Bonn convicted him of aggravated tax evasion and sentenced him to eight years in prison. The lawyer was also ordered to pay back almost €13.7 million. The verdict can be appealed.
Berger became an adviser to banks, funds, and investors after working as a public official in the regional tax administration in Germany
The 72-year-old was arrested last year in Switzerland, where he had been since 2012. He was extradited to Germany in February.
Another case against Berger related to the "cum-ex" scheme is ongoing at the state court in Wiesbaden.
Dozens of people have been charged in the Cum-ex case in Germany, including bankers, traders, lawyers, and financial advisers. A total of ten countries are involved in the investigation.
The scandal has also tainted German Chancellor Olaf Scholz over meetings he had as Hamburg mayor with a private bank. Scholz has denied any wrongdoing.