The Industrial Revolution in Iron: The Impact of British Coal Technology (on Google Books), mentions an iron works at Saint-Julien in the Saint-Etienne region. At around this time, it seems 'English-type' ironworks were being set up and workers were hired from Staffordshire and Wales  - Joseph Bessy, the owner of the Saint-Julien works, apparently hired most of his workers from Bilston.
This was during the 1820s - as time wore on, the local workers were trained and replaced the foreign ones.  There's a fair bit of information in the book about money etc. 
Saint-Julien-Molin-Molette might be the Saint-Julien in the Saint-Etienne region that is mentioned.