Who is exempt from the special tax and when

(a) Properties of entities of the federal, State, or city governments shall be exempt from the special tax, except as otherwise provided by subsection (b). No other properties or entities within a district shall be exempt from the special tax, unless expressly exempted in the ordinance of formation. (b) If a federal, State, or city entity owning property, including property held in trust for any beneficiary, grants a leasehold or other possessory interest in the property to a nonexempt person or entity, the special tax shall, notwithstanding subsection (a), be levied on the leasehold or possessory interest and shall be payable by the owner of the leasehold or possessory interest. When entering into a lease or other written contract creating a possessory interest for a nonexempt person or entity, the federal, State, or city entity shall include in the contract a statement that the property interest shall be subject to special taxation pursuant to this chapter. Failure to comply with the requirement shall not, however, invalidate the contract or affect the special tax or the obligation of the nonexempt person or entity to pay the special tax.