in France, a high government official, similar to the intendant before the French Revolution. The French prefectoral corps was created in 1800 by Napoleon Bonaparte, who endowed it with great prestige and influence. At that time the prefects were the administrators of the départements; they were responsible for public order and good government and for ensuring that the policy of the central government was effectively carried out throughout the country. Napoleon called them empereurs au petit pied (“miniature” or “small-scale emperors”).

Under succeeding regimes the power of the corps increased, but its prestige declined. Since they were dependent for office on the whim of the central government, the prefects became concerned primarily with police and elections, and one of their principal functions was to ensure the government a safe parliamentary majority. They reached the height of their power under the Second Empire (1852–70). During the first decades of the Third Republic (1870–1940), the position was weakened by the frequent nomination of new men by successive governments. The prefects, however, became increasingly concerned with social and economic problems, and after World War II, while retaining responsibility for public order and good government, they became the dynamic element in the provinces for promoting and coordinating social policies.

The prefectoral system continued into the Fifth Republic (from 1959). One prefect was responsible for each département, and subprefects were responsible for the arrondissements within the département. Prefects were appointed by the president of the republic and were responsible to the minister of the interior. The prefect was the general administrator of the département, the chief executive officer of its general council (the locally elected departmental assembly), and the principal police authority. He was also the supervisor of the communes (local and municipal governments) in the département, and his approval was required for many administrative acts of these local authorities. After France's départements were grouped into larger administrative units called régions (1955–64), a prefect appointed by the national government administered each région with the help of a regional council.

Under the decentralization law of 1982, many of the powers of the prefect were transferred to presidents elected by councils in the départements and régions. The prefects were renamed commissaires (commissioners), and their main responsibility was to ensure that regional and departmental authorities were complying with national legislation. The law was subsequently modified to restore some of the authority previously held by the prefect, and the title of prefect was reintroduced in 1986.

in ancient Rome, any of various high officials or magistrates having different functions.

In the early republic, a prefect of the city (praefectus urbi) was appointed by the consuls to act in the consuls' absence from Rome. The position lost much of its importance temporarily after the mid-4th century BC, when the consuls began to appoint praetors to act in the consuls' absence. The office of prefect was given new life by the emperor Augustus and continued in existence until late in the empire. Augustus appointed a prefect of the city, two praetorian prefects (praefectus praetorio), a prefect of the fire brigade, and a prefect of the grain supply. The prefect of the city was responsible for maintaining law and order within Rome and acquired full criminal jurisdiction in the region within 100 miles (160 km) of the city. Under the later empire he was in charge of Rome's entire city government. Two praetorian prefects were appointed by Augustus in 2 BC to command the praetorian guard; the post was thereafter usually confined to a single person. The praetorian prefect, being responsible for the emperor's safety, rapidly acquired great power. Many became virtual prime ministers to the emperor, Sejanus being the prime example of this. Two others, Macrinus and Philip the Arabian, seized the throne for themselves.

By AD 300 the praetorian prefects virtually directed the civil administration of the empire. They executed judicial powers as delegates of the emperor, organized tax levies, and supervised provincial governors. They also commanded troops and served as quartermasters general to the emperor's court. Under the emperor Constantine I the Great (reigned 312–337), the praetorian prefects were stripped of their military commands, but they retained their judicial and financial functions and remained the highest officers of the empire.