The next eldest son of Josse. He performed the body organ and harpsichord and constructed music. Jean-Joseph trained the harpsichord at Ghent and was the organist at St. Baaf Cathedrl. A year or two later he could head to Paris, ultimately getting the organist for the ambassador of Portugal. The efforts he designed to structure include functions for harpsichord: concertos and divertimenti with an intermittent violin. A few of his concertos illustrate a pre-Classical sonata framework.