37 The finding of bias on the part of an expert requires in particular the assessment of facts and evidence that comes within the competence of the contracting authorities and the administrative or judicial control authorities.
38 It should be pointed out that neither Directive 89/665 nor Directive 2004/18 contains specific provisions in that regard [and, it is worth adding, Directive 2014/24 does not contain any specific procedural rules as to how to assess these issues either].
39 The Court has consistently held that, in the absence of EU rules governing the matter, it is for every Member State to lay down the detailed rules of administrative and judicial procedures for safeguarding rights which individuals derive from EU law. Those detailed procedural rules must, however, be no less favourable than those governing similar domestic actions (principle of equivalence) and must not render impossible in practice or excessively difficult the exercise of rights conferred by EU law (principle of effectiveness) (see judgment in Club Hotel Loutraki and Others, C‑145/08 et C‑149/08, EU:C:2010:247, paragraph 74 and the case-law cited).
40 In particular, the detailed procedural rules governing the remedies intended to protect rights conferred by EU law on candidates and tenderers harmed by decisions of contracting authorities must not compromise the effectiveness of Directive 89/665 (see judgment in Uniplex (UK), C‑406/08, EU:C:2010:45, paragraph 27 and case-law cited).
41 It is not, as a general rule, contrary to those principles for an expert’s bias to be established in a Member State solely on the basis of an objective situation in order to prevent any risk that the public contracting authority could be guided by considerations unrelated to the contract in question and liable, by virtue of that fact alone, to give preference to one tenderer.
42 Concerning the rules on evidence in that regard, it should be pointed out that ... the contracting authorities are to treat economic operators equally and non-discriminatorily and to act in a transparent way. It follows that they are assigned an active role in the application of those principles of public procurement.
43 Since that duty relates to the very essence of the public procurement directives (see judgment in Michaniki, C‑213/07, EU:C:2008:731, paragraph 45), it follows that the contracting authority is, at all events, required to determine whether any conflicts of interests exist and to take appropriate measures in order to prevent and detect conflicts of interests and remedy them. It would be incompatible with that active role for the applicant to bear the burden of proving, in the context of the appeal proceedings, that the experts appointed by the contracting authority were in fact biased. Such an outcome would also be contrary to the principle of effectiveness and the requirement of an effective remedy ... in light, in particular, of the fact that a tenderer is not, in general, in a position to have access to information and evidence allowing him to prove such bias.
44 Thus, if the unsuccessful tenderer presents objective evidence calling into question the impartiality of one of the contracting authority’s experts, it is for that contracting authority to examine all the relevant circumstances having led to the adoption of the decision relating to the award of the contract in order to prevent and detect conflicts of interests and remedy them, including, where appropriate, requesting the parties to provide certain information and evidence.
45 Evidence such as the claims in the main proceedings relating to the connections between the experts appointed by the contracting authority and the specialists of the undertakings awarded the contract, in particular, the fact that those persons work together in the same university, belong to the same research group or have relationships of employer and employee within that university, if proved to be true, constitutes such objective evidence as must lead to a thorough examination by the contracting authority or, as the case may be, by the administrative or judicial control authorities.
46 Subject to compliance with the obligations under EU law, and specifically with those referred to in paragraph 43 above, the concept of ‘bias’ and the criteria for it are to be defined by national law. The same applies to the rules relating to the legal effects of possible bias. Thus, it is for national law to determine whether, and if so to what extent, the competent administrative and judicial authorities must take into account the fact that possible bias on the part of the experts had no effect on the decision to award the contract (C-538/13, paras 37 to 46, emphasis added).
In the case at hand, a contract for translation services into Polish had been tendered by several EU Institutions under the lead of the Parliament. The first evaluation of the offers produced a shortlist were Euroscript Polska was ranked first and Agencja MAart second.
The Parliament proposed to award the contract to Euroscript, subject to its furnishing of sufficient proof of not being affected by any applicable exclusion ground. The decision was communicated to all tenderers and a 14-day period for the request of further particulars on this decision, including their own evaluation reports and the relative advantages of the selected offer, started.
The GC framed the analysis of this situation in the following way:
53 [...] according to the case-law, the fact that a tenderer, even though he has no intention of doing so, is capable of influencing the conditions of a call for tenders in a manner favourable to himself constitutes a situation of a conflict of interests. In that regard, the conflict of interests constitutes a breach of the equal treatment of candidates and of equal opportunities for tenderers (Joined Cases C‑21/03 and C‑34/03 Fabricom  ECR I‑1559, paragraphs 29 and 30, and Case T‑160/03 AFCon Management Consultants and Others v Commission  ECR II‑981, paragraph 74).
Member States shall ensure that contracting authorities take appropriate measures to effectively prevent, identify and remedy conflicts of interest arising in the conduct of procurement procedures so as to avoid any distortion of competition and to ensure equal treatment of all economic operators.
The concept of conflicts of interest shall at least cover any situation where staff members of the contracting authority or of a procurement service provider acting on behalf of the contracting authority who are involved in the conduct of the procurement procedure or may influence the outcome of that procedure have, directly or indirectly, a financial, economic or other personal interest which might be perceived to compromise their impartiality and independence in the context of the procurement procedure.
57 The applicant also argues that the successful tenderer enjoyed an unfair advantage because of the former seconded national expert’s participation in a previous call for tenders as a member of the evaluation committee.
58 In that respect, it must be pointed out that, according to the Commission, the applicant has not proved that the former seconded national expert participated in the drafting of the successful tenders for Lots 1 to 9. In order to prove that he did, the applicant has produced statements prepared by three of its employees, describing conversations they had with the former seconded national expert at the dinner on 13 November 2012 [...]. However, it must be noted that those statements do not show conclusively that the former seconded national expert participated in the drafting of the successful tenders for Lots 1 to 9, since the impressions of the applicant’s employees as to whether that was the case have been expressly contradicted by the person concerned himself. In any event, even if those statements did prove such participation by the former seconded national expert, it must be noted that their probative value is weak since they were made by the applicant’s employees, who have a particular interest in the contract being awarded to the applicant.
59 In the present case, even supposing that the former seconded national expert did participate in the drafting of the successful tenders, it must be pointed out that the applicant, by the evidence which it has submitted, has proved neither the participation of the former seconded national expert in the preparation of the call for tenders at issue, nor the unfair advantage that the successful tenderer allegedly enjoyed because its new employee was a member of a tender evaluation committee in a previous, similar procurement procedure. Furthermore, as the Commission rightly points out, the applicant has provided language training services to the EU institutions since 2008 and collaborated with the Commission in the context of the contract previous to the call for tenders at issue, with the result that it had information on the needs and requirements of the European institutions, notwithstanding the fact that the contract previous to the call for tenders at issue, contrary to the present call for tenders, did not include blended learning.
60 It follows from all the foregoing that the applicant has not proved that the fact that one of the successful tenderer’s employees worked at the Commission as a seconded national expert gave it an unfair advantage in the procurement procedure at issue of such a kind as to infringe the principles of non-discrimination and of equal treatment. Nor, moreover, has the applicant proved the infringement of the principle of transparency (T-4/13 at paras 57-60, emphasis added).