He moved to Nantes after the submission of the duc de Mercœur, in 1598, and married Jeanne Cremé.
The couple had at least three children - Paul, Anne (who married Jérôme Bachot), and Charles the Younger (Nantes, 1606-Rome, 1689).
Shortly afterwards he converted to Catholicism and on 1 March 1615 the king made him designer of the repairs and fortifications in the towns of Brittany, replacing Jean Guilbaud at an annual wage of 500 livres.
According to Frédéric Villot, cited by Auguste Jal, on his way to Rome Claude Lorrain met Charles Errard the Younger with his father and his brother Paul in Marseille.
[1] It is unknown when Charles Errard the Elder returned to France, but he died in Nantes.