Recital 45

(45)The competitive procedure with negotiation should be accompanied by adequate safeguards ensuring observance of the principles of equal treatment and transparency. In particular, contracting authorities should indicate beforehand the minimum requirements which characterise the nature of the procurement and which should not be changed in the negotiations. Award criteria and their weighting should remain stable throughout the entire procedure and should not be subject to negotiations, in order to guarantee equal treatment of all economic operators. Negotiations should aim at improving the tenders so as to allow contracting authorities to buy works, supplies and services perfectly adapted to their specific needs. Negotiations may concern all characteristics of the purchased works, supplies and services including, for instance, quality, quantities, commercial clauses as well as social, environmental and innovative aspects, in so far as they do not constitute minimum requirements.