Considered a Creole because of his birth in La Louisiane, de Marigny belonged to a family that was part of the minor provincial nobility of France.

After her husband's death, the widow Madeleine de Marigny married the colony's royal engineer, Ignace François Broutin.

[4] Like his (probable) father-in-law Guillaume de Lisle, Geographer to the King, Antoine became an accomplished cartographer.

Kerlerec had both men arrested and sent back to France (along with the Royal Colonial Treasurer Jean Baptiste d'Estrehan, with whom he had also clashed).

In France, the men continued their dispute with Kerlerec and were imprisoned in the Bastille for a short time.