"According to the French bioethics law, DNA testing is only allowed for medical, scientific or judicial purposes. The main concern is that paternity tests and medical DNA tests shouldn’t be done without supervision. But the ban also extends to genealogical DNA tests."

https://www.myfrenchroots.com/dna-testing-in-france/

From my own experience, my wife has several lines that I know originated in France (either directly or through early Quebec settlers) from verified records and nothing shows up in her Ancestry results. Also, the ethnicity reports in general might as well be labeled for "entertainment purposes only" - they are not consistent from revision to revision, and are often flat out wrong when matched against hundreds of years of documentation. Theoretically they might get better over time, but I manage four DNA results including my own and the ethnicity results are never accurate.