On 12 November 1919, Prince Sixtus of Bourbon-Parma was married to Hedwige
de la Rochefoucauld, the daughter of Armand de La Rochefoucauld, Duke de Doudeauville,
Duke de Bisaccia and his wife, Princess Louise
Radziwill. Hedwige's younger sister, Marie de La Rochefoucauld, married
Henri-Antoine-Marie de Noailles, the 11th
Prince de Poix. The marriage lacked the authorization of Sixtus's elder half-brother,
Elias, Duke of Parma, and was considered
non-dynastic until 1959, at which time Elias's son,
Robert Hugo, Duke of Parma, inheriting his father's position as head of the family, recognized the marriages of his uncles Sixtus and Xavier. Together, they had one daughter: Princess Isabella (1922–2015) who married a distant cousin Count Roger de la Rochefoucauld on 23 June 1943. They divorced in 1966. They had five sons and six grandchildren. The peace
Treaty of Saint-Germain, gave France the right to confiscate permanently the property of those who had fought in enemy armies during the war. As Sixtus's half-brother, Elias, had served in the Austrian army, the French government expropriated
Chambord castle, owned by the Bourbons of Parma. Because Prince Sixtus and his brother Xavier had fought with the
Allied side, they took their brother Elias to court demanding a greater share of the family inheritance. They claimed that the former legal agreement was contrary to French law. In 1925, a French court upheld Sixtus and Xavier's claim, but the appeals court overturned the verdict in 1928. The French
Court of Cassation upheld it in 1932. ==Publications==