“These artworks are stained with the blood of Biafra’s children,” wrote Chika Okeke-Agulu, an art history professor at Princeton, in an impassioned Instagram post three weeks ago calling for a halt to the sale of two wooden statues made by the Igbo people of Nigeria. Mr. Okeke-Agulu believes the items were looted in the late 1960s during the country’s brutal civil war.

But the auction went ahead on Monday at Christie’s in Paris. The life-size male and female figures, described by Christie’s as “among the greatest sculptures of African art,” sold to an online bidder for 212,500 euros with fees, about $238,000. The price was well below the pre-sale estimate of €250,000 to €350,000.

The sculptures originated from southeast Nigeria, a region devastated by one of the late 20th century’s bloodiest civil conflicts. Biafra’s unsuccessful three-year struggle to gain independence, which ended in 1970, claimed the lives of more than a million people, most of whom died of starvation.

Mr. Okeke-Agulu, who grew up in the Biafra war zone, near where the statues were made, said in his Instagram post that Christie’s Igbo figures were among many artifacts stolen by intermediaries at the behest of European and American dealers and collectors, such as the renowned French collector Jacques Kerchache.