Ms Lagarde is to be questioned before a magistrate in May over her role in the awarding of financial compensation to businessman Bernard Tapie in 2008.
Ms. Lagarde, who took over as IMF chief in 2011, denies any wrongdoing.
Her apartment was searched last month as part of the ongoing investigation.
As finance minister, Ms. Lagarde referred Mr. Tapie’s long-running dispute with bank Credit Lyonnais to an arbitration panel, which awarded him 400m euros (£340m) damages.
Mr. Tapie was a supporter of ex-President Nicolas Sarkozy.
Critics say she abused her authority but Ms. Lagarde denies any wrongdoing.
When asked about the court case at the end of a news conference on Thursday she replied: “There is nothing new under the sun and ever since 2011 I had known very well that I would be heard by the investigating commission of the Courts de Justice.”
“I’ll be very happy to travel for a couple of days to Paris but it’s not going to change my focus, my attention and my enthusiasm for doing the work that I do.”
Last month, the IMF issued a statement affirming its confidence in Ms. Lagarde.
Her flat was raided by French police in March, but she has not been formally charged with any crime.
Her lawyer, Yves Repiquet, told the AFP news agency she would now “finally have the opportunity to provide the court with explanations and clarifications that will exonerate her of any criminal responsibility”.
The BBC’s Christian Fraser, in Paris, says investigators suspect Mr. Tapie was granted a deal in return for his support of President Sarkozy in the 2007 election.
There is speculation in France that Ms. Lagarde could yet be placed under formal investigation in this case, he adds.
The origins of the case date back 20 years.
Mr. Tapie, who has long been active in French business, sporting and political circles, sued Credit Lyonnais over its handling of the sale in 1993 of sportswear brand Adidas, in which he was a majority stakeholder.
After years in the courts, the case was referred by Ms. Lagarde to an arbitration panel in 2007 and she approved its decision to award damages.
Critics said the case should not have been settled by private arbitration, since public money was at stake in the bank, which was part-owned by the state.
The settlement Mr. Tapie received is believed to be a far greater sum than he would likely have received from the courts.
In an interview in January, Ms. Lagarde stood by her decision, saying it was “the best solution at the time”.
However, our correspondent says that Ms. Lagarde’s position at the IMF could be in jeopardy if she is placed under formal investigation.
Her term as IMF chief does not expire until 2016, but amid the complexities of Europe’s economic crisis this is a distraction she can ill afford, he adds.