This article describes how a number of relatively obscure Protestants took part in the Parisian scientific and economic life of the first decades of the seventeenth century. By offering portraits of several mathematical practitioners as well as  entrepreneurs and evoking the relationships they maintained, it illustrates the powerful cohesion within the Huguenot community. Those examples form an empirical ground for testing and questioning Protestant exceptionalism theses as they have been formulated by both Weber and Merton.