1. Where contracting authorities intend to purchase works, supplies or services with specific environmental, social or other characteristics they may, in the technical specifications, the award criteria or the contract performance conditions, require a specific label as means of proof that the works, services or supplies correspond to the required characteristics, provided that all of the following conditions are fulfilled:

(a) the label requirements only concern criteria which are linked to the subject-matter of the contract and are appropriate to define characteristics of the works, supplies or services that are the subject-matter of the contract;

(b) the label requirements are based on objectively verifiable and non-discriminatory criteria;

(c) the labels are established in an open and transparent procedure in which all relevant stakeholders, including government bodies, consumers, social partners, manufacturers, distributors and non-governmental organisations, may participate;

(d) the labels are accessible to all interested parties;

(e) the label requirements are set by a third party over which the economic operator applying for the label cannot exercise a decisive influence.