Many were nobles from i know. Even Henri IV a noble man, who became king of France, was huguenot.
He renounced his faith for catholicism but made "edith de Nantes" . It was a bill to enforce tolerance to all chistian faith in France.
The new teaching attracted sizeable portions of the nobility and urban bourgeoisie.
First the nobles converted then usually they pass on their religion to their subjects.
South of France was notoriously a protestantism fort.
Atch : They came to Ireland, Uk and even Germany.
Thomas de Mazière, actual minister of defense in Germany, come from a noble Huguenot family.