Where the performance or functional requirements include environmental characteristics, these may be defined by reference to all or part of an ecolabel, provided that:
1° That the ecolabel is appropriate for defining the characteristics of the supplies or services covered by the contract;
2° That the information contained in the ecolabel has been drawn up on the basis of scientific information;
3° That the ecolabel has been drawn up by means of an open and transparent procedure;
4° That the ecolabel and its detailed specifications are accessible to any interested party.