Doorway entrance to the Residence Laffemas on the Rue St Julien le Pauvre

You will find mulberry trees scattered everywhere in most of France, trees on which silkworms feed on, and this was due largely to the belief by Barthélemy de Laffemas, an uneducated French mercantilist in the 17th century who was the controller-general of commerce under King Henri IV, that France expand its silk industry. The project was a total failure, due to the fact that a cold climate is unfavourable to the raising of silkworms.

Here is an excerpt from An Austrian Perspective on the History of Economic Thought, vol. 1, Economic Thought Before Adam Smith by Murray N Rothbard from Ludwig Von Mises Institute, which is a scathing criticism of Raffemas’s commercial ideas:

The first French mercantilist of note was Barthélemy de Laffemas (1545–1612), an uneducated son of a very poor Protestant family in Dauphine. All his life he was the servitor of Henry of Navarre, the Protestant pretender, rising in 1582 to the exalted post of honorary tailor and valet to his master. When Henry of Navarre became King Henry IV, Laffemas’s fortune was made, and he became in 1601 controller-general of commerce and head of the Commission of Commerce, to remain so until the king’s death. Laffemas comes to our attention because of the literally dozens of execrably written pamphlets he produced during his decades in power, on behalf of the mercantile system which he was helping to put into place in France.

Everyone who opposed his views, according to Laffemas, was selfish, ignorant, and/or a traitor, and should be dealt with accordingly. All who disobeyed the regulations and prohibitions should suffer confiscation of their goods as well as death.

One of Barthélemy de Laffemas’s daftest projects, which as controller-general he did his best to put into effect, was to make France self-sufficient in one of her favorite luxury imports: silks. Many of his pamphlets and practical efforts were devoted to force-feeding an enormous expansion of the French silk industry, hitherto small and confined to the south of France.

Laffemas advocated a law compelling all property owners, including the clergy and monasteries, to plant mulberry trees. He also claimed magical medicinal properties for mulberries: they would cure toothache and stomach trouble, relieve burns, chase away vermin, and be an antidote to poisons.

Even though Laffemas persuaded the king to pour hundreds of thousands of livres into fostering the growth of mulberry trees and silk culture, and the king duly ordered each diocese in France to establish a nursery of 50,000 mulberries, the great silk experiment proved an abject failure. The climate of most of France indeed proved inhospitable. [Likewise,] the mass of the French clergy understandably dragged their feet at suddenly being forced to become silk producers. France continued to be a heavy net importer of silks.