A German media group, Constantin Medien, which claims it lost out in a deal to sell the Formula One Group, has launched legal action against the 83-year-old British tycoon and three other defendants.
Constantin is seeking over £100 million ($160 million) in damages.
Ecclestone, chief executive of the F1 group and a resident of Gstaad in the canton of Bern, says the claim "lacks any merit" and has denied being party to any form of "conspiracy".
The key charge levelled against him is that in 2005 he paid $44 million in bribes to a German banker to engineer the sale of F1 to current owners CVC Capital Partners.
Ecclestone told the court that he felt forced to make payments to the banker because the banker led him to believe that he would create problems with the tax authorities.
"It is true," said Ecclestone.
"That's what I have always said."
Swiss prosecutors have also opened an investigation into the issue, which is the latest challenge to Ecclestone's authority in a sport he has helped to turn into a billion-dollar business.
The trial is expected to last several weeks.