When the purchaser is subject to Book IV and organises a design contest, economic operators who have submitted services in accordance with the contest rules are awarded a premium. The amount of this premium is equal to the estimated price of the studies to be carried out, reduced by a maximum of 20%. The purchaser specifies in the tender documents the conditions under which the premium may be reduced or waived. It pays this premium to the participants in the competition on the recommendation of the jury.