“The Marquis de Coigny used to gamble with the Prince des Dombes, and lost a lot ; one day, he said through his teeth : he is happier than a legitimate child. The prince had not heard the remark ; but charitable souls (there are always some) brought it to him. He flew into a rage, and sent to call M. de Coigny to a duel. They met on the road to Versailles, in the middle of the night. The ground was covered with snow ; they fought with torches : M. de Coigny was killed on the spot ; they put him back in his carriage, which they overturned in a ditch. He was said to have died from the fall. The king, who loved him very much, did not know the truth until after the death of the Prince of Dombes, and some people even believed that he never knew it. »
In 1750, he gained the titles of prince d'Anet and comte de Dreux, when his mother gave him both estates three years before she died. Little seen at the court of his cousin Louis XV of France, he preferred living at the Château d'Anet, which he continued to embellish. In order to supply water for his gardens, he created a hydraulic system which he installed in the park of the domain near the river Eure. He also enjoyed hunting on his large estate of Eu.
