Fauveau was fascinated by Gothic art, and more generally by the religious art of the Middle Ages, whose archaic purity, which she labelled "primitivism", perfectly expressed her religious feelings. Her deeply-held religious convictions ruled every aspect of her art, which included many objects linked to private devotions. She elevated the domestic holy water font, found in so many homes, to the level of a precious object made especially for her rich clients. "I hope that the Devil will be annoyed with me for this unusual series" she wrote to the Comtesse de La Rochejaquelein.
She had developed the model of the Holy Water Font with an Angel even before arriving in Florence. In front of a Roman building with two turrets, an angel extends a wing to protect the basin of holy water, under which nestle birds and aquatic plants along with a verse from psalm 16 "Sub umbra alarum tuarum protege me", "Hide me in the shadow of your wings". For Princess Sophie of Arenberg, Fauveau designed the model of the font for the Adoration of the Cross, presented by an angel with outspread wings. Finally, the Saint Louis font refers to the piety of the legitimist Catholics. Surprisingly, Fauveau produced very few objects for churches: the Christ on the Cross for Saint-Aubin-de-Baubigné, "on a beautiful cross in the style of Giotto", is a rare example of this.