It's a small curved line that sits above the letter and has a few different uses in French:
* Indicates a lost "s": In some cases, the circumflex marks the location of a "s" that used to be present in the word but has since disappeared. For example, "tête" (head) used to be "teste".
* Distinguishes pronunciation: The circumflex can also be used to distinguish the pronunciation of words that are otherwise spelled the same. For example, "cœur" (heart) is pronounced differently from "coeur" (the old spelling of "coeur").
* Indicates a specific vowel sound: In some cases, the circumflex can indicate a specific vowel sound, such as in "pâté" (meat paste).
It's important to note that the circumflex is not always present over the "e" in French. It's only used in specific situations.