BOUYID v. BELGIUM JUDGMENT 29 establish such necessity. The Court consequently finds that the applicants’ dignity was undermined and that there has therefore been a violation of Article 3 of the Convention. 103. In any event, the Court emphasises that a slap inflicted by a lawenforcement officer on an individual who is entirely under his control constitutes a serious attack on the individual’s dignity. 104. A slap has a considerable impact on the person receiving it. A slap to the face affects the part of the person’s body which expresses his individuality, manifests his social identity and constitutes the centre of his senses – sight, speech and hearing – which are used for communication with others. Indeed, the Court has already had occasion to note the role played by the face in social interaction (see S.A.S. v. France [GC], no. 43835/11, §§ 122 and 141, ECHR 2014, concerning the ban on wearing clothing intended to conceal the face in public places). It has also had regard to the specificity of that part of the body in the context of Article 3 of the Convention, holding that “particularly because of its location”, a blow to an individual’s head during his arrest, which had caused a swelling and a 2 cm bruise on his forehead, was sufficiently serious to raise an issue under Article 3 (see Samüt Karabulut v. Turkey, no. 16999/04, § 41, 27 January 2009). 105. The Court reiterates that it may well suffice that the victim is humiliated in his own eyes for there to be degrading treatment within the meaning of Article 3 of the Convention (see paragraph 87 above). Indeed, it does not doubt that even one unpremeditated slap devoid of any serious or long-term effect on the person receiving it may be perceived as humiliating by that person. 106. That is particularly true when the slap is inflicted by lawenforcement officers on persons under their control, because it highlights the superiority and inferiority which by definition characterise the relationship between the former and the latter in such circumstances. The fact that the victims know that such an act is unlawful, constituting a breach of moral and professional ethics by those officers and – as the Chamber rightly emphasised in its judgment – also being unacceptable, may furthermore arouse in them a feeling of arbitrary treatment, injustice and powerlessness (for consideration of this kind of feeling in the context of Article 3 of the Convention, see, for example, Petyo Petkov v. Bulgaria, no. 32130/03, §§ 42 and 47, 7 January 2010). 107. Moreover, persons who are held in police custody or are even simply taken or summoned to a police station for an identity check or questioning – as in the applicants’ cases – and more broadly all persons under the control of the police or a similar authority, are in a situation of vulnerability. The authorities are consequently under a duty to protect them (see paragraphs 83-84 above). In inflicting the humiliation of being slapped by one of their officers they are clearly disregarding this duty.