What is Contrefacon?

Legal Definition
French law. Counterfeit. This is a bookseller's term, which signifies the offence of those who print or cause to be printed, without lawful authority, a book of which the author or his assigns have a copyright. Merl. Rep. h. t.
-- Bouviers Law Dictionary
Legal Definition
In French law. The offence of printing or causing to be printed a book, the copyright of which is held by another, without authority from him. Merl. Repert.
-- Black's Law Dictionary