B. NON-DISCRIMINATION (PART II) 18. The principle of non-discrimination is central to all international human rights instruments and to the Charter of the United Nations. Article 7 of the Convention explicitly includes nationality among the prohibited grounds of discrimination. Treaty bodies have also interpreted the prohibition of discrimination to include non-nationals, such as migrant workers, regardless of legal status and documentation.22 The rights in Part III of the Convention also apply to all migrant workers and members of their families, including those in an irregular situation. Therefore, any differential treatment based on nationality or migration status amounts to discrimination unless the reasons for such differentiation are prescribed by law, pursue a legitimate aim under the Convention, are necessary in the specific circumstances, and proportionate to the legitimate aim pursued.23 19. Article 7 requires States parties “to respect and to ensure” to all migrant workers and members of their families without discrimination the rights provided for in the Convention. Article 7 does not provide an autonomous right. Its application is limited to those rights of migrant workers and members of their families in an irregular situation that are protected in the Convention, and in particular Part III. Article 7 covers both de jure and de facto discrimination. In this context, de jure refers to discrimination that exists in the law, and de facto refers to discrimination that exists in fact or has an effect even though not formally or legally recognized. States parties shall respect the prohibition of discrimination by ensuring that their laws, regulations and administrative practices do not discriminate against migrant workers and members of their families. The Committee is of the view that merely addressing de jure discrimination will not ensure de facto equality. Therefore, States parties shall protect the rights under the Convention for all migrant workers by adopting positive measures to prevent, diminish and eliminate the conditions and attitudes which cause or perpetuate de facto discrimination against them. 20. Article 7 prohibits both direct and indirect discrimination against migrant workers. In line with the jurisprudence of other international human rights mechanisms, indirect discrimination against migrant workers occurs when a law, policy or practice appears neutral at face value, but has a disproportionate impact on their rights. For example, requiring birth certificates for school enrolment may disproportionately affect migrant workers in an irregular situation, who often do not possess, or have been denied, such certificates. C. PROTECTION OF CIVIL AND POLITICAL RIGHTS (PART III) 1. Protection against violence 21. Migrant workers in an irregular situation, particularly women, are at increased risk of ill-treatment and other forms of violence at the hands of both private actors, including employers, and State officials which includes sexual violence, beatings, threats, psychological abuse, and denial of access to medical care, for example. Under article 16, paragraph 2, States parties have an obligation to protect all migrant workers and members of their families against violence, physical injury, threats and intimidation, whether by public officials or by private individuals, groups or institutions. This obligation requires States parties to: (a) Adopt and implement legislation prohibiting such acts; (b) Effectively investigate cases of abuse and violence; (c) Prosecute and punish those responsible with appropriate punishments; 22 Committee on Economic, Social and Cultural Rights, general comment No. 20 (2009) on non-discrimination in economic, social and cultural rights, para. 30. 23 See Human Rights Committee, general comment No. 18 (1989) on non-discrimination, para. 13; and Committee on Economic, Social and Cultural Rights, general comment No. 20 on the right to education, para. 13. 62