The government says that any children in the Chadian army were recruited by rebel movements who have since been integrated into the government.
Both the UN and HRW dispute that claim.
Quality of life
Children's lives are being threatened all across Chad but particularly in the east near the border with Darfur, where L'Arche de Zoé allegedly took the 103 children. They live amongst armed conflict between the government and rebel groups, cross-border raids by militias from neighbouring Sudan, and inter-ethnic violence.
Many lack access to food, water and healthcare.
"Children [in eastern Chad] never have enough to eat," opposition politician Ngarlejy Yorongar told IRIN, accusing the government of neglect.
The government says it offers free emergency care in its hospitals, and has set up nutrition and health centres but Yorongar said health centres are rare, and when they exist, they lack medicines. "The government has the means to help children, but not the will," he said.
Save the Children estimates that at least half the 180,000 displaced Chadians and 230,000 Sudanese refugees in eastern Chad are children. "What the displaced, refugee and local populations have access to now is mainly provided by local NGOs and international aid agencies," said Aurélie Lamazière, of Save the Children UK's emergencies department.
"I just find the reaction to the 103 children by the French and Chadian authorities and the press slightly disproportionate compared with the tens of thousands of children who are also in need of some sort of assistance," Lamazière told IRIN.
Chad's UNICEF representative, Mariam Coulibaly Ndiaye, said the state of education in Chad was deplorable.
"When you go to a village, sometimes there is no school. When there are schools, there are not enough teachers. When communities get together to find teachers, they have not been trained," she said.