53 Pa. Stat. § 6924.304
A city of the second class in which is located a sports stadium or arena that has received public funds in connection with its construction or maintenance may enact a publicly funded facility usage fee upon those nonresident individuals who use such facility to engage in an athletic event or otherwise render a performance for which they receive remuneration. The fee may be a flat dollar amount or a percentage of the individual's income attributable to such individual's usage of the facility. If the fee is a percentage, it may not exceed three percent of the earned income of the individual attributable to the usage of the facility. If any fee is imposed, those individuals liable for the fee shall be exempt from any earned income tax imposed by the city of the second class pursuant to this chapter and any such tax imposed under section 652.1 of the act of March 10, 1949 (P.L. 30, No. 14), known as the "Public School Code of 1949." Should a court of competent jurisdiction determine this provision to be invalid for any reason, persons subject to the publicly funded facility usage fee shall not be exempt from any previously applicable earned income tax.
53 P.S. § 6924.304