Charlotte (or Charlotta) du Riez or Du Rietz, née De Geer (1744–1820) was a Swedish noblewoman (Baroness), known as a love object of King Gustav III. It is unknown whether or not she was ever physically involved with the monarch.
She was the daughter of Marshal Charles De Geer and married Lieutenant Anders Rudolf du Rietz in 1765. She is described as a well educated and cultivated intellectual, with an interest in chemistry. From July to September 1768, both Charlotte and Crown Prince Gustav were in Paris, France, and there were involved in a strong emotional friendship; this has been referred to as the only love affair Gustav III ever had. According to tradition, his affection ended when he realized that she had several lovers. The real nature of the relationship has been debated, with no specific conclusions of fact available.
The statement about the consummation of the marriage of Gustav III made by Adolf Fredrik Munck describes the sexual history of Gustav III and thereby also the character of his relationship with Charlotte Du Rietz.[1] In his statement, Munck reports that Gustav had only one partner before Charlotte Du Rietz, "The wife of an English sea captain" in Gothenburg in 1766, but neither in that case nor in the relationship with Charlotte Du Rietz was there apparently any other physical contact than touching "without effect".[2] This was the reason to why the most famous courtesan of Stockholm, Catharina Norman, was hired in 1771 to remove the king's virginity.[3] After her meeting with the monarch, Catarina Norman reported that: "His Majesty is terribly shy and utterly unuse to it", and that it had not been possible to perform intercourse.[4] The relationship between Charlotte Du Rietz and Gustav III was thereby not likely sexually consummated.
Correspondence between Du Rietz and Gustav III is kept at Uppsala University Library.