International Monetary Fund (IMF) Managing Director Christine Lagarde delivers opening remarks at the IMF’s 17th Jaques Polak Annual Research Conference in Washington November 3, 2016. REUTERS/Kevin Lamarque

PARIS (Reuters) - IMF chief Christine Lagarde will ask for a postponement of a trial aimed at establishing her role in a 400-million-euro ($428 million) payout to businessman Bernard Tapie as another investigation of the case is ongoing, her lawyer told Reuters.

France’s highest appeals court rejected Lagarde’s appeal against a judge’s order in December for her to stand trial at the Cour de Justice de la Republique (CJR), a special court that tries ministers for crimes in office.

Lagarde was France’s finance minister from 2007 to 2011 before becoming Managing Director of the International Monetary Fund.

The trial, scheduled to take place from Dec. 12-20, will be only the fifth in the history of the tribunal, made up of three judges and six lawmakers from the lower and upper houses of parliament.

Lagarde is accused of negligence with the result that public funds were misused by improperly approving the decision to allow an out-of-court arbitration in a dispute with Tapie, a supporter of conservative former president Nicolas Sarkozy.

The case goes back to when Tapie sued the state for compensation after selling his stake in sports company Adidas to Credit Lyonnais in 1993. He said the bank had defrauded him after it later resold his stake for a much higher sum.

“The very existence of public funds misuse is not established,” Lagarde’s lawyer Patrick Maisonneuve said, adding the CJR was not in a position to rule on the issue because another wider investigation to determine other responsibilities was taking place.

In that separate procedure, six people, including Tapie, have been put under formal investigation.

The court can rule on Lagarde’s request at the start of the trial or go forward and rule at the end of the hearings.