In the interest of clarity, simplicity and effectiveness, the powers to supervise and enforce the obligations under this Regulation should be conferred to the competent authorities in the Member State where the main establishment of the provider of intermediary services is located, that is, where the provider has its head office or registered office within which the principal financial functions and operational control are exercised. In respect of providers that are not established in the Union, but that offer services in the Union and therefore fall within the scope of this Regulation, the Member State where those providers appointed their legal representative should have competence, considering the function of legal representatives under this Regulation. In the interest of the effective application of this Regulation, all Member States or the Commission, where applicable, should, however, have competence in respect of providers that failed to designate a legal representative. That competence may be exercised by any of the competent authorities or the Commission, provided that the provider is not subject to enforcement proceedings for the same facts by another competent authority or the Commission. In order to ensure that the principle of ne bis in idem is respected, and in particular to avoid that the same infringement of the obligations laid down in this Regulation is sanctioned more than once, each Member State that intends to exercise its competence in respect of such providers should, without undue delay, inform all other authorities, including the Commission, through the information sharing system established for the purpose of this Regulation.