Harris Beach LLP signed the 2.5-year sublease on a full floor at 500 Fifth Ave. on Monday. But sublessor Harris Interactive authorized some of the firm's 113 employees to move in last Friday, according to Insignia/ESG broker Ivan Hillman. Hillman and Jerry Friedman represented both parties on behalf of Insignia.

"Members of the real estate community are being particularly responsible and cooperative" in the aftermath of the Trade Center attacks, Hillman tells GlobeSt.com. "They have done things that are not done under normal circumstances and one example is letting tenants move in before the final papers were executed."

The 58-story, 650,000-sf tower at 42nd Street and Fifth Avenue, also known as the Salmon Tower after developer Walter J. Salmon, was designed by Shreve Lamb & Harmon and built in 1930. The architectural firm went on to build the Empire State building the following year.