Pfeiler & Langen, Südzucker and Nordzucker, along with seven unnamed individuals were found to have been fixing prices, sales territories and quotas between them for many years, the Federal Cartel Office in Bonn said.
The three German sugar producers agreed on various strategies between them aimed at pushing up sugar prices across the board, whether they sold to households or the food industry.
The manufacturers agreed "to keep to their traditional sales territories and not get in the way of the other cartel members," said Cartel Office president Andreas Mundt in a statement.
"Quantities of sugar were more likely to be exported abroad than be sold to customers in the competition's territory," he said.
At times, industrial customers told the authority, the illegal agreements had resulted in considerable price hikes and even supply shortages of sugar.
Price fixing for sugar first began in the mid-1990s and continued until 2009, when the companies were searched by the cartel office.
For its extensive cooperation with the investigation, Nordzucker had received a "considerably reduced fine," said the authority.
The fines are not yet final and the companies have the chance to appeal at the higher court in Düsseldorf.
Südzucker bore the brunt of the fine and must pay €195.5 million.
A statement from the company said: “After due consideration of all aspects Südzucker has accepted the notice in a settlement agreement.”
Südzucker added the fine was the result of an agreement with the Cartel Office which led to a “significant” reduction in their payment.It is the second big fine to hit the German food and drink industry this year. In January the Cartel Office fined some of the country's biggest breweries for price fixing.