"He was captured by a heavily armed group which killed two Nigerians and is probably linked to Aqim or the groups which are today in Mali," Hollande told Europe 1 radio.
About 30 gunmen stormed a residence, where expatriate workers were staying, in the village of Rimi on Thursday evening.
They killed a security guard and a neighbour and kidnapped the man, who works for French alternative energy company Vergnet which has a wind-power project in Katsina.
Two of his colleagues, who were also staying at the residence, were absent at the time.
They threw an explosive device at the police station so as to avoid being pursued, according to local police.
They say that the Islamist group Boko Haram, which is active in northern Nigeria but has not in Katsina until now, was probably not behind the kidnapping.
Boko Haram is believed to have links with Aqim, which is holding seven French citizens hostage.
"We have to be firm when it comes to terrorism while at the same time maintaining contacts to free them,” Hollande said, adding that kidnapping is a “commercial operation” to raise money for arms.
Rimi is near the border with Niger, where Aqim kidnapped four of the hostages last year, and Niger has a frontier with Mali, where Islamist armed groups that have taken control of the north of the country.
The UN Security Council on Thursday accepted a plan for an African armed force to intervene in Mali, if negotiations fail to reunify the country.