(A). “Le guet de Montfaucon.” A man hanged. Montfaucon is an eminence near Paris, once used as the Tyburn or place of execution. At one time it was crowded with gibbets, but at the Revolution they were destroyed, and it became the dustbin of the city, “Une voirie pour les immondices de Paris et Vêscarrissage des chevaux.” In 1841 this sink of corruption and infection was moved to “La plaine des Vertus,” surely a strange satire on the word.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894