It' is unlikely that the letter that Meir Ben Simeon of Narbonne proposed to send to King Louis IX - who will be the successor of St. Louis in 1297 - either reached him or either sent to him. Only one copy was preserved with other texts of this famous Talmudist, in a provencal manuscript of 14th century, known under the name of Mihemet mitsvah. This pseudo-missive presentatio has a particular interest in the corpus of "supplications" and other "implorations" for the improvement of the fate of the Jews of the kingdom of France under the reign of this anti-Jewish king if any, in that it does to intervene - probably for the first time in this litterature - economic arguments, based on the Scriptures. By prohibiting the Jews from lending interest and by depriving them of a professional activity which allows them to live decently, writes Meir, the King endangers the economy of his own country which, by the use of the loan, fails to . A masterpiece of the history of the Jews of France in the thirteenth century, this letter decisively enriches what we know about the relationship between this "holy" king and his Jewish subjects, whose corner he knows how to ostracize them. At the same time as burning their books by "full cartloads" in the Paris square.