She was the daughter of Marshal Baron Charles De Geer and Catharina Charlotta Ribbing and married Lieutenant Anders Rudolf du Rietz in 1765.
In February 1768, it was noted that Charlotte Du Rietz and Eva Helena Löwen flirted with Crown Prince Gustav and attempted to seduce him.
At the same time, Gustav was under pressure to consummate his marriage to Sophia Magdalena of Denmark at his summer residence Ekolsund Castle, and he was blamed for his flirtation by Charlotta Sparre.
In September, Gustav made an official inspection journey through Bergslagen and visited Lövstad Castle, the childhood home of Du Rietz, where he ended their flirtation after he heard rumors that she had more lovers.
[3] After her meeting with the monarch, Catharina Norman reported that: "His Majesty is terribly shy and utterly unused to it", and that it had not been possible to perform intercourse.