Olivier Salgado said the peacekeepers were on patrol Monday about 30 kilometers north of the city of Kidal. He said the peacekeepers were slightly injured and had been transferred to Kidal for treatment.
Security remains tenuous in the region, as al-Qaida-linked militants remain active even after a French-led military operation to oust them from power last year.
Tuareg rebels from the National Movement for the Liberation of the Azawad are also present in the area.
Three Chadian soldiers were wounded by gunmen in the same region earlier this month as they were pursuing suspects in an attack on a military camp.