17 U.S.C. 412. Registration as prerequisite to certain remedies for infringement
In any action under this title, other than an action brought for a violation of the rights of the author under section 106A(a), an action for infringement of the copyright of a work that has been preregistered under section 408(f) before the commencement of the infringement and that has an effective date of registration not later than the earlier of 3 months after the first publication of the work or 1 month after the copyright owner has learned of the infringement, or an action instituted under section 411(c), no award of statutory damages or of attorney's fees, as provided by sections 504 and 505, shall be made for—
(1) any infringement of copyright in an unpublished work commenced before the effective date of its registration; or
(2) any infringement of copyright commenced after first publication of the work and before the effective date of its registration, unless such registration is made within three months after the first publication of the work.