With the publication of a new guideline on green marketing, the Swiss Unfair Competition Commission has provided greater clarity in the assessment of the admissibility of marketing communications with environmental or climate-related content. In particular, the Guideline sets out clear rules on the requirements for admissible marketing communications with an environmental reference and the associated requirements for evidence. In a legal environment characterized by vague legal provisions and considerable discretion given to the competent authorities, this new Guideline provides important clarification.