Case C-796/18: Judgment of the Court (Fourth Chamber) of 28 May 2020 (request for a preliminary ruling from the Oberlandesgericht Düsseldorf — Germany) — Informatikgesellschaft für Software-Entwicklung (ISE) mbH v Stadt Köln (Reference for a preliminary ruling — Public procurement — Directive 2014/24/EU — Article 2(1)(5) — Article 12(4) — Article 18(1) — Concept of contract for pecuniary interest — Contract between two contracting authorities pursuing common public interest objectives — Making available of software for the coordination of fire-fighting operations — Absence of monetary payment — Link to a cooperation agreement providing for the mutual provision of additional modules of this software free of charge — Principle of equal treatment — Prohibition on placing a private undertaking in a privileged position in relation to its competitors)