In addition to what @Openopenopenopen@lemmy.world said, if you look at the fleurs-de-lis wikipedia article, there's a whole section titled "Religion and art".

There is an argument that, "The Fleurdelisé is more cultural than religious," but separating those two is extremely difficult. IMHO, it's pretty ethnocentric to think symbols like that have become so ingrained in our culture that they are no longer religious, while assuming symbols like hijab are purely religious.