Anglicisms in French is actually a funny subject. According to different sources, roughly 45% of all English words have a French origin. Thus, there's a lot of overlap between English and French. Some words, such as camping, parking and flirting are considered anglicisms in French, but they are actually words from the Old French that did a full round-trip from French to English to French.

Although the stems are ok and related to other French words (camping -> camp, campement, camper ; parking -> parc, parquer ; flirting <-> conter fleurette), I think what can shock the purists is this ending is -ing which does not sound French at all and is not grammatically French.