One of the most common aggravating circumstances is the repeated infringement. This means that there has been a previous ruling against the undertaking although it may not have necessarily given rise to a sanction;  a finding of infringement or a warning are sufficient.  The first decision does not have to be final; it may still be subject to legal review. Further, the fact that the two infringements are contemporaneous is of no relevance to the sanction where the undertaking continued to participate in the second even though it had been found guilty of the first. The provisions to which the sanctions relate can be merely similar as in the case of Article 101 TFEU and former Article 53 ECSC.

The practices do not have to have been implemented on the same market or concern the same products. There is also no requirement for all the practices to have been adopted by the same entity – the fine is imposed on the ‘undertaking’ within the meaning of competition law and can therefore apply to various companies belonging to the same group. However, where the development of the structure and control of the companies concerned is particularly complex, the Commission must give precise evidence to support a finding that the same ‘undertaking’ repeated offending conduct. The parent company sanctioned for the past infringing conduct of a subsidiary must have been the addressee of the decision in question and the Commission must state in a clear and precise manner in the Statement of Objections relative to the second infringement, in what capacity and to what extent the undertaking in question was involved in the decisions to which it refers. In the same way, a subsidiary which was not the addressee of an initial decision which had ruled against the parent company without establishing that they formed an economic unit cannot have its fine increased for a later infringement on the basis of a repeat infringement.

With regard to the temporal scope of the repeated infringement, the competition authorities first of all held that as it was not subject to any statute of limitations, an increase in the fine for a repeat offense was not disproportionate even if the first decision pronouncing the fine was handed down twenty years earlier and that the absence of a maximum period between two rulings when taking the repeat infringement into account did not constitute a violation of the principles of the legality of sanctions and legal certainty. Later, the Court of Justice clarified that EU law does not authorize the Commission to take account of an earlier infringement with no limitation in time considering that a period of fifteen years between two offenses could not give rise to an increase for repeat infringement.