Guillaume de Grandchamp de Grantrie was French Ambassador to the Ottoman Empire from 1566 to 1571.

From 1566, he notably proposed to the Ottoman Court a plan, devised by Charles IX of France and Catherine de Medicis, to settle French Huguenots and French and German Lutherans in Moldavia, in order to create a military colony and a buffer against the Habsburgs. This plan also had the added advantage of removing the Huguenots from France, then a major issue due to the French Wars of Religion.^[2] He offered himself to become the Voyvoda of Moldavia, who would pay a tribute of 20,000 ducats to the Ottomans.^[2]

In 1569, during the tenure of Grandchamp, the Ottomans seized French and foreign ships under French flags in order to recover a debt estimated to 150,000 Écus or ducats that Charles IX owed to the Ottoman money-lender Joseph Nasi. After protests, only the French ships and goods were kept, totalling an amount of about 42,000 ducats.^[3] The goods were at least partially returned with the signature of the 1569 Capitulations.^[1]