 Complete the following phrase:  The Paris police force was completely re-organized after the fall of Napoleon III and the Commune; the sergents de ville were replaced by the gardiens de la paix publique Guardians of the Public Peace, which by June 1871 had 7,756 men under the authority of the Prefect of Police named by the national government. Following a series of anarchist bombings in 1892, the number was increased to 7,000 guardians, 80 brigadiers and 950 sous-brigadiers. In 1901, under the prefect Louis Lépine, in order to keep up with the technology of the time, a unit of policemen on bicycles called the hirondelles after the brand of the bicycles was formed. They numbered 18 per arrondissement and reached 600 by 1906 for the whole city. A unit of river police, the brigade fluviale, was organized in 1900 for the 