Article 13³²
Termination of financial obligations

(1) Rights of the Organisation to the payment of a fee to the European Patent Office shall be extinguished after four years from the end of the calendar year in which the fee was due.  

(2) Rights against the Organisation for the refunding by the European Patent Office of fees or sums of money paid in excess of a fee shall be extinguished after four years from the end of the calendar year in which the right arose. 

(3) The period laid down in paragraphs 1 and 2 shall be interrupted in the case covered by paragraph 1 by a request for payment of the fee and in the case covered by paragraph 2 by a reasoned claim in writing. On interruption it shall begin again immediately and shall end at the latest six years after the end of the year in which it originally began, unless, in the meantime, judicial proceedings to enforce the right have begun; in this case the period shall end at the earliest one year after the judgment enters into force.

(4) The President of the European Patent Office may waive action for the enforced recovery of any sum due if the sum to be recovered is minimal or if such recovery is too uncertain.