RIVADULLA DURÓ v. SPAIN DECISION A. Complaints under Articles 9 and 10 of the Convention 24. In view of the substance of the applicant’s complaints, the Court, being the master of the characterisation to be given in law to the facts of the case, considers that they fall to be examined under Article 10 of the Convention. 25. The Court reiterates in this connection that freedom of expression constitutes one of the essential foundations of a democratic society and one of the basic conditions for its progress and for each individual’s self - fulfilment. It is applicable not only to “information” or “ideas” that are favourably received or regarded as inoffensive or as a matter of indifference, but also to those that offend, shock or disturb (see, for example, Otegi Mondragon v. Spain, no. 2034/07, § 48, ECHR 2011; Erkizia Almandoz v. Spain, no. 5869/17, § 37, 22 June 2021; and Z.B. v. France, no. 46883/15, § 52, 2 September 2021). 26. The convictions in issue clearly constituted an interference with the applicant’s right to freedom of expression as guaranteed by Article 10 § 1 of the Convention. The Court is further satisfied that the interference was prescribed by law (see paragraph 16 above) and pursued a legitimate aim, namely national security and public safety, within the meaning of Article 10 § 2 of the Convention. The main question in the present case is therefore whether the interference was “necessary in a democratic society” (see, for example, Otegi Mondragon, cited above, § 49, and Perinçek v. Switzerland [GC], no. 27510/08, §§ 196-97, ECHR 2015). 27. In exercising its supervisory jurisdiction, the Court’s task is not to take the place of the competent national authorities but rather to review under Article 10 the decisions they delivered pursuant to their power of appreciation. The Court has to look at the interference complained of in the light of the case as a whole and determine whether the reasons adduced by the national authorities to justify it are “relevant and sufficient” and whether it was “proportionate to the legitimate aim pursued”. In doing so, the Court has to satisfy itself that the national authorities applied standards which were in conformity with the principles embodied in Article 10 and, moreover, that they relied on an acceptable assessment of the relevant facts (see, among many other authorities, Yavuz and Yaylalı v. Turkey, no. 12606/11, § 44, 17 December 2013; Erkizia Almandoz, cited above, §§ 37-40; and Z.B. v. France, cited above, §§ 53-54). The Contracting States have, under Article 10, a certain margin of appreciation in judging the necessity and extent of an interference with the freedom of expression protected by that provision (see Mouvement raëlien suisse v. Switzerland [GC], no. 16354/06, § 59, ECHR 2012, and Z.B. v. France, cited above, § 58). 11