Career
He became Governor of Bangkok and Mergui, but was eventually captured by the Siamese during the 1688 Siamese revolution. De Beauregard was then made governor of the city of Mergui after the revolt against the English there in July 1687. De Beauregard was named governor by King Narai of Siam in the place of the Englishman, Samuel White.
De Beauregard was part of the retreat of the French troops of De Bruant there, following the 1688 Siamese revolution.
Large-scale attacks were launched on the two French fortresses in Siam, Bangkok and Mergui, and on 24 June, the French had to abandon their garrison at Mergui. Du Bruant and de Beauregard managed to escape under fire and with many casualties by seizing a Siamese warship, the Mergui.
The captives seem to have been enslaved.