131. Effect of nullity of registration on licence contract

Where, before the expiration of the licence contract, the registration is declared null and void, the licensee shall no longer be required to make any payment to the licensor under the licence contract, and shall be entitled to repayment of the payments already made :

Provided that the licensor shall not be required to make any repayment, or shall be required to make repayment only in part, to the extent that he can prove that any such repayment would be inequitable under all the circumstances, in particular if the licensee has effectively profited from the licence.