However, rebel leaders in Chad say the presence of foreign forces will not bring stability to the country.
The announcement came after Deby met Dominique de Villepin, the French prime minister.
France has a military contingent stationed in Chad, its former colony, including fighter jets which give logistical and intelligence support to Chadian government forces.
Deby said: "Chad accepts the United Nations proposal to place forces on its frontier to protect the population and stabilise the sub-region."
He did not specify when the force might be deployed.
The two leaders said the force would be deployed on the Chadian side of the border with Sudan, where three years of conflict have caused tens of thousands of deaths.
Peace force problems
"A UN force in Chad is not a solution... the international community should invest in a national reconciliation for Chad"
Deby accuses neighbouring Sudan of backing Chadian rebels opposed to him and cross-border raids by Arab militias.
The Sudanese government denies the charges and has in turn accused Deby of supporting Darfur rebels opposed to the government in Khartoum.
Mahamat Nour, an anti-Deby leader, whose fighters carried out raids in N'Djamena, the capital of Chad, in April, said a foreign peace force for Chad would not bring stability and risked being attacked by Chadians.
"A UN force in Chad is not a solution. On the contrary, the international community should invest in a national reconciliation for Chad," he said.