The definition and the duty to maintain the commercial secret is regulated by Commercial Law. Note the EU Directive 2016/943 on harmonisation the protection of undisclosed know-how and business information (trade secrets) came into force in July 2016. Transposition must be completed before June 2018. See: http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2016.157.01.0001.01.ENG&toc=OJ:L:2016:157:TOC