International Monetary Fund chief Christine Lagarde is facing questions at a special Paris court Thursday over her role in the 400 million euro ($520 million) pay-off to a controversial businessman when she was France's finance minister.

The court hearing threatens to sully the reputations of both Lagarde and France. The payment was made to well-connected entrepreneur Bernard Tapie as part of a private arbitration process to settle a dispute with state-owned bank Credit Lyonnais over the botched sale of Adidas in the 1990s. It is seen by many in France as an example of the cozy relationship between big money and big power in France.

Lagarde has earned praise for her negotiating skills as managing director of the IMF through Europe's debt crisis and is seen as a trailblazer for women leaders. Her decision to let the Adidas dispute go to private arbitration rather than be settled in the courts has drawn criticism, and French lawmakers asked magistrates to investigate.

Lagarde, smiling at reporters, left her Paris apartment Thursday morning and appeared at a special court that handles cases involving government ministers. She has denied wrongdoing.

At the time of the payment, Tapie was close to then-French President Nicolas Sarkozy, who was Lagarde's boss. Critics have said the deal was too generous to Tapie at the expense of the French state, and that the case shouldn't have gone to a private arbitration authority because it involved a state-owned bank.