Neither side would comment on the suit.

NorthStar is based at 527 Madison Ave. David Hamamoto, formerly the co-head of the Whitehall funds at Goldman Sachs & Co. and a partner there, and Edward Scheetz, formerly a partner at Apollo Real Estate Advisors, founded the company together. In 1997 they raised $300 million from qualified institutional buyers, including Walt Disney Corp. and Northwestern Mutual Life. NorthStar filed its S-11 in 1998 to allow it to trade shares.

NorthStar went on to buy a controlling interest in Ian Schrager Hotels, a company formed by the co-creator of Studio 54. Schrager's hotels are among the trendiest, frequented by celebrities from the entertainment and modeling industries. NorthStar also committed $35 million to help capitalize a company funding mortgages on approximately 30 of US Franchise Systems' holdings. It also invested in a joint venture that owns 350 Washington St. in Boston. In 1998, NorthStar teamed with Andrew Davidoff and Emmes' senior management to purchase a controlling interest in Emmes & Co. LLC for $55 million.