A Manhattan federal judge has sanctioned Cleary Gottlieb Steen & Hamilton for improperly trying to dissuade a witness from testifying about his dealings with the Republic of Congo, which the New York law firm is representing in a dispute with a foreign hedge fund.

In an opinion issued last week, Southern District of New York Judge Loretta Preska said Cleary had acted in “bad faith” by contacting witness M�dard Mbemba, a French-Congolese businessman and onetime close friend of Congolese President Denis Sassou-Nguesso, and telling him his participation in a deposition could “destabilize” or “hurt” Congo.