Where a purchaser decides to enter into a single contract even though the contract relates to objectively separable services which are subject, on the one hand, to the ordinary law governing contracts set out in Book I of Part Two or Book II thereof relating to partnership contracts and, on the other hand, to the ordinary law governing concession contracts set out in Book I of Part Three, the contract is subject to :
1° To the ordinary law governing contracts as set out in Book I of Part Two or Book II relating to partnership contracts if the estimated value excluding tax of the services covered by these books exceeds the European thresholds applicable to public contracts set out in the notice annexed to this code;
2° To the provisions applicable to its main purpose if this is not the case.