Businesses referring in their advertising to results of product tests carried out by independent test institutes (e.g. Stiftung Warentest = Stiwa, Which? or Que choisir?), have to indicate, under well-established German case-law, the source where the test report is published. The consumer will thus be informed in how far the respective test is up to date and may obtain further information.
In cases, in which there is no such publication, e.g. mere quality labels issued upon a test by a third party, the advertiser has to provide the relevant test criterias on its own, as the Federal Court of Justice found in its judgment of July 21, 2016 (ref.: I ZR 26/15 – “LGA tested“). Consequently, at least a short summary of the criteria should be presented on a referenced website. It should, in particular, become apparent whether the critera only correspond to statutory minimum requirements (if any) or go beyond them.