The outgoing Inspector General of Police (IGP) Mohammed Adamu has handed over to his successor Usman Alkali Baba.
The ceremony took place at the Force Headquarters, Abuja.
Earlier, Vice President Yemi Osinbajo decorated Baba with his new rank in the State House, Abuja.
In attendance were his wife, some top government officials and senior police officers.
Buhari appointed Baba, a former DIG, Finance and Administration, on Tuesday.
Born in 1963, Baba joined the Force in 1988 as an Assistant Superintendent and became a Commissioner in January 2014.
The ex-Force Secretary, is an alumnus of Bayero University, Kano, and the University of Maiduguri (UNIMAID), Borno.
He served as AIG Zone 4 Makurdi, Zone 7 Abuja, and was Commissioner of Police Federal Capital Territory (FCT) command, Delta command, among others.