Nau's sister Claire in 1563, also joined Mary's service. An account of the death of Mary, Queen of Scots, mentions that Ruisseau was Claude Nau's brother-in-law, a beau frere, and Albert Fontenay was Claude Nau's brother or half brother.

Nau was presented by the Duke of Guise, Mary's nephew, to Henri III of France. The King gave him diplomatic accreditation and sent him to Elizabeth I of England.