E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Jean des Vignes (French).
So the jonglers call the poupée to which they address themselves. The French Protestants in the sixteenth century called the host Jean, and the word is pretty well synonymous with buffoon. Jean des Vignes was a drunken marionette performer of considerable ability; Jean was his name, des Vignes his sobriquet. Hence when a person does a bad action, the French say, Il fait comme Jean des Vignes; an illicit marriage is called le mariage de Jean des Vignes, and a bad fellow is un Jean des Vignes. Hence Assoucy says, Moi, pauvre sot, plus sot que Jean des Vignes!