The purchaser may require a particular label provided that the characteristics demonstrated by this label:
1° Are related to the subject of the contract within the meaning of Article L. 2112-3;
2° Enable the works, supplies or services which are the subject of the contract to be defined.
The purchaser may require a particular label, even where not all the characteristics demonstrated by that label are expected, provided that it identifies those it requires in the consultation documents.
The purchaser may refer to a label which partially meets the conditions mentioned in this article, provided that he identifies in the consultation documents only those characteristics which he requires.