The reference salary used as a basis for determining the special allowance is set on the basis of the remuneration on which contributions to the unemployment insurance scheme were based for the last twelve calendar months prior to the last day of work paid to the person concerned, up to a limit of twice the ceiling provided for in article L. 241-3 of the Social Security Code. It is calculated in accordance with the rules defined under the unemployment insurance scheme provided for in Chapter II of Title II of Book IV of Part V of this Code.