Around 20 gunmen in pick-up trucks shot at the French troops, who returned fire, destroying one of the three vehicles, Gilles Jaron said.
He said no French soldiers were killed in the clash. It was not clear whether the opposing side suffered any casualties.
Deeply impoverished Central Africa has been gripped by crisis since the mainly Muslim Seleka alliance seized power in a March 2013 coup led by Michel Djotodia.
Splinter groups of Seleka rebels later went rogue, embarking on a campaign of killing, raping and looting.
The abuses prompted members of the Christian majority to form vigilante groups, unleashing a wave of tit-for-tat killings that has left thousands dead and close to a million displaced.
Djotodia, now in exile in Benin, was replaced as president by interim leader Catherine Samba Panza in January after failing to stop the bloodshed.
Despite a French-led international peacekeeping presence, the country remains deeply unstable.