The Affair of the Placards (French: Affaire des Placards) was an incident in which anti-Catholic posters appeared in public places in Paris and in four major provincial cities: Blois, Rouen, Tours and Orléans, overnight during 17 October 1534. One was actually posted on the bedchamber door of King Francis I at Amboise, an affront and an alarming breach of security that left him shaken. The Affaire des Placards brought an end to the conciliatory policies of Francis, who had formerly attempted to protect the Protestants from the more extreme measures of the Parlement de Paris, and also of the public entreaties for moderation of Philip Melanchthon.
The placards carried the title "Genuine articles on the horrific, great and unbearable abuses of the papal mass, invented directly contrary to the Holy Supper of our Lord, sole mediator and sole savior Jesus Christ" This provocative title was a direct attack on Catholic conceptions of the Eucharist. They supported Zwingli's position on the Mass which denied the physical presence of Christ in the eucharist.
The individual who has been traditionally credited as the chief inspiration, if not the direct author of the placards, was the French Protestant leader Guillaume Farel, but it seems that Antoine de Marcourt, a pastor of Neuchâtel from Picardy, was the real author: Antoine Froment averred that "these placards were made at Neuchâtel in Switzerland by a certain Antoine Marcourd". Writing anonymously the following month, Marcourt took credit for the placards in the address to benevolent Readers of his anonymous "Most useful and salutary little treatise of the holy Eucharist", published at Neuchâtel, 16 November 1534, in which he avers "I have been moved by true affection to compose and edit in writing some true Articles on the unbearable abuses of the Mass. Which Articles I wish to be published and posted throughout the public places of the land..."