Chadian troops shot dead a Christian protester on Monday in the Central African Republic's capital, Bangui, the day after French troops killed three alleged Séléka militiamen and Muslims protested against their presence in the country.
The Chadian soldiers, part of the African Union's Misca force, opened fire on a Christian demonstration outside Bangui airport on Monday after protesters stoned their vehicle.
At least one person was killed and another wounded.
French troops intervened to take away the victims.
The several hundred demonstrators were demanding the departure of President Michel Djotodia, who became the majority-Christian country's first Muslim president thanks to the Séléka rebellion although he subsequently disbanded the militias.
They also want Chadian troops to leave, claiming that Chad's President Idriss Deby of masterminded the rebellion and that Chadian and Sudanese mercenaries have perpetrrated the worst crimes in several months of murder, rape and pillage by Séléka fighters.
On Sunday several thousand Muslims demonstrated against the French presence, accusing the French of disarming Séléka but not Christian anti-balaka armed groups.
French troops killed three Séléka fighters, claiming that they were preparing to fire on them.
Amnesty International estimates that 1,000 people have been killed since an anti-balaka offensive on 5 December.