In what appears to be the first decision of its kind in New York, a Manhattan federal judge has disqualified an entire law firm from defending a corporate client against a discrimination claim because an associate at the firm attempted to mediate the dispute before the plaintiff filed suit.

The ruling, by Southern District Judge William H. Pauley III, is based on a section of the state’s attorney ethics rules which bars a lawyer from from mediating a dispute and then representing one of parties.