This article aims at describing how some little known Protestants took part to the scientific and economic life of Paris during the first decades of the seventeenth century. Through the portraits of several individuals, whether they were mathematical practitioners or entrepreneurs, and through the évocation of their relationships, this article shows the strong cohesion of the huguenot community. Those examples form an empirical ground on which the protestant exceptionalism thesis, as phrased by Weber or Merton, can be assayed and questioned.