I'm guessing it's because of the author being French, as another commenter pointed out, but, it's plenty common for loan words to end up having a more specific

I'm guessing it's because of the author being French, as another commenter pointed out, but, it's plenty common for loan words to end up having a more specific or outright different meaning in a different language We're talking French and Japanese here so let's look at one going the opposite way - the french avec to アベック/ abekku. In French it just means 'with' - eggs with ham, let's go to the beach with friends, whatever. In Japanese it is used to mean that you're romantically with someone, and is used as a noun to stand in for the word couple. Or for a more specific usage example, high ball in English refers to any mixed drink where the base spirit is a lower volume of the drink than the mixer, e.g. gin and tonic, screwdriver, etc. In Japan a ハイボール / hai barru refers almost universally to whiskey and soda water. Of course other highball drinks are served there, but will tend to get a more specific name, such as a shochu highball being a チューハイ / chuhai. It's more rare for this to happen with a chain of original word -> loan word -> loan word, but still something that happens - it's called 'reborrowing' a word. Another example of this would be the Chinese having reborrowed matcha to mean Japanese-style green tea. It's not silly or wrong to utilize the word anime in the west to refer specifically to Japanese-style animation.