The béni-oui-oui were Muslim yes-men who collaborated with the French colonial institutions in North Africa.
The word is derived from "beni", the Arabic for "sons of", e.g. used to name tribes in Arabic, and "oui", the French for "yes", so it means "the tribe of the yes-men", a group of persons who systematically give their unanimous approval when asked for. An explanation given in the Bulletin de la Société d'anthropologie de Paris in 1893 is that some "natives" systematically answered "oui, oui" (yes, yes) when a colonial administrator asked them any question.[1]
The word was already in use in 1888-1889 in Metropolitan France (used to label some members of the National Assembly[2]) and Algeria[3] and in 1919 in Morocco.[4]
The word is nowadays currently used in French for situations pertaining neither to North Africa nor to politics.