Earliest Known French Ciphers

The earliest known specimen of French ciphertext is from January 1526 (or possibly September 1525). This is a few months earlier than the earliest mentioned in a scholarly paper (2018). This and other French ciphers during the reign of Francis I are described in the new article "French Ciphers during the Reign of Francis I".
It includes some undeciphered ciphers, which are now mentioned in "Unsolved Historical Ciphers".