MAURITANIA

Article 14 of the Convention on the Rights of the Child protects a child's freedom of thought, conscience and religion.
Article 28 guarantees the right of the child to education.

Article 18:
"1. Everyone shall have the right to freedom of thought, conscience and religion. This right shall include freedom to have or to adopt a religion or belief of his choice, and freedom, either individually or in community with others and in public or private, to manifest his religion or belief in worship, observance, practice and teaching.
2. No one shall be subject to coercion which would impair his freedom to have or to adopt a religion or belief of his choice.

Article 6 guarantees the "right of everyone to the opportunity to gain his living by work which he freely chooses or accepts". A substitute service that is much longer than military service can be seen as a disproportionate restriction of this right.
Article 13 guarantees the right to education.

Article 18 of the Universal Declaration of Human Rights:
"Everyone has the right to freedom of thought, conscience and religion; this right includes freedom to change his religion or belief, and freedom, either alone or in community with others and in public or private, to manifest his religion or belief in teaching, practice, worship and observance."

The preambel to the Charter of the United Nations states that "we the peoples of the United Nations" are determined (...):

• to reaffirm faith in fundamental human rights, in the dignity and worth of the human person, in the equal rights of men and women and of nations large and small, and
• to establish conditions under which justice and respect for the obligations arising from treaties and other sources of international law can be maintained

The African Charter on the Rights and Welfare of the Child guarantees the rights of children in those African countries that have ratified it. Especially relevant are:

Article 9 (1) (Freedom of Thought, Conscience, and Religion)

"Every child shall have the right to freedom of thought conscience and religion."

The African Charter on Human and Peoples' Rights (ACHPR) from 1981, which entered into force in 1986, is Africa's oldest human rights instrument.

Article 8 of the ACHPR states: “Freedom of conscience, the profession and free practice of religion shall be guaranteed. No one may, subject to law and order, be submitted to measures restricting the exercise of these freedoms.” The right to conscientious objection to military service could be derived from this article, similar to article 18 of the ICCPR and article 9 of the ECHR.