* Abigaïl: This is the most common French equivalent of "Abby," derived from the biblical name Abigail.
* Abbie: This is a common nickname for Abigail, and it can also be used in French.
* Abby: You can also simply use "Abby" in French. While not technically French, it's widely understood and used.
The best option will depend on the situation. If you're looking for a formal name, "Abigaïl" is the most appropriate. If you want a casual or friendly name, "Abbie" or even just "Abby" might be better.