63In the second place, as regards the applicant’s complaint that the Commission breached the principle of proportionality in taking the Peroxygen Products decision into consideration for the purpose of establishing repeated infringement, it must be borne in mind that, according to the case-law, the principle of proportionality requires that the measures adopted by the institutions must not exceed what is appropriate and necessary for attaining the objective pursued. When it comes to the calculation of fines, the gravity of infringements has to be determined by reference to numerous factors and it is important not to confer on one or other of those factors an importance which is disproportionate in relation to other factors. In that context, the principle of proportionality requires the Commission to set the fine proportionately to the factors taken into account for the purpose of assessing the gravity of the infringement and also to apply those factors in a way which is consistent and objectively justified (see Case T-43/02Jungbunzlauer v Commission [2006] ECR II-3435, paragraphs 226 to 228 and the case-law cited, and Joined Cases T-456/05 and T-457/05Gütermann and Zwicky v Commission [2010] ECR II-1443, paragraph 264).