The three adults and four children of the Moulin-Fermier family, who were kidnapped near Cameroon's Waza nature reserve on 19 February, were handed over to Cameroonian authorities overnight, Biya said.
They are in good health, according to reports.
The Nigerian and French governments played an important role in the release, officials have said, without giving more details.
France in February said it would not hold direct talks with the kidnappers and President François Hollande later said that no ransoms would be paid for any French hostages now being held.
Nigeria took the same line.
Boko Haram claimed responsibility for the kidnapping, not far from the Nigerian border, some time after it took place.
Seven other French citizens are being held hostage in the Sahel region and Al Qaida has threatened reprisals against France because of its role in the anti-Islamist offensive in Mali.