Duc d'Enghien's execution memorial - Chateau de Vincennes

In 1804 Napoleon, then first consul, received intelligence that connected the Duke d'Enghien with the conspiracy to overthrow him then being planned by Georges Cadoudal and Charles Pichegru. The report was false, but Napoleon ordered Enghien's arrest, and French gendarmes crossed the Rhine secretly and seized him. He was brought to the castle of Vincennes, where a court-martial was hurriedly gathered to try him, and he was shot in the castle moat. Actually, his only crime was to have been born a Bourbon... ( Encyclopædia Britannica )

Pinpoint where photos were taken on this XVIII th century engraving