I mean the crux here is really "as we call it". Without knowing what your junior high teacher means when he says "feudalism" there is no way to say how accurate his claim is. My guess is that your teacher is refering to the feudal revolution in France where, very basically, the feudal system underwent several iterations in which the fiefs were broken up into ever smaller parts with ever smaller obligations form ever lower ranks of nobles but again, there is no way to know without asking him. However, if that is what he's refering to I would still argue that his statement is but one possible point of view based on one applicable definition of feudalism that is absolutely not universally accepted by historians. The concept of feudalism is and has always been fuzzy because it was not a contemporary term, it's a 19th century classification that has several possible definitions of differing scope. To say that areas outside of southern france were not "properly feudal" is to apply a needlessly narrow definition of the word and does nothing to help you understand what feudalism was and how it affected the world.

If I were you I would ask him if he can define feudalism in such a way that it includes all legal and military customs in southern france but not the legal and military customs of contemporary northern france. That description would help me understands what he means by "properly feudalism".