He was most famous for having signed the war treaty "Convention de Brandenburg" in the name of King Louis XV.

During the Seven Years' War he was taken prisoner and exchanged at the Battle of Rossbach in 1757, and fought against Prussia in Corbach and Kassel.

On 7 September 1759, he signed a military treaty known later as the "Convention de Brandebourg".

This agreement, concluded with the representative of the Prussian armies, General Major Baron Johann Jobst Heinrich von Buddenbrock, stipulated that the hospitals, wounded soldiers and lazarets as well as the medical personnel would not be considered as fighting units.

On 7 June 1749, he married Marie Claude Jeanne Julie de Coetmen; they had five children: