The review fee is collected by the SISA/EP for its own benefit and its amount is fixed by the EPO. It is to be paid within one month from the date of the notification of lack of unity of invention (see GL/PCT‑EPO B‑XII, 10.4).[Rule 45bis.6(c); ]
Source: http://www.epo.org/law-practice/legal-texts/html/guidelinespct/e/a_iii_6_3.htm
Date retrieved: 17 May 2021