Well, OK, please remember, you did ask. First a bit of a disclaimer, if you're an American who happens to be of French decent I'm not talking about you, I hope I'm not anyway.
I've had ample opportunity to observe the Frenchman in his natural habitat (you know, France) and I've never been (collectively) treated so rudely in my life. I hate to paint a whole people with a broad brush but I've both experienced and observed this phenomenon so many times it must be a representative sample. I have no idea what could justify the Frenchman's attitude that he is somehow superior to whom ever he happens to be belittling but it happens all the time. At first I though this rudeness was reserved for foreigners but the more exposure I had, the more I observed one Frenchman talking down to another who he believed to be less sophisticated.
I do have to admit I was pleasantly surprised by a French SASS shooter by the alias of "Trusty Dog" who I meet at End of Trail a few years ago. He was clearly very intelligent and recognized he was a guest making a first impression but I also perceived him to be very genuine and not the kind of man who would treat you differently in front of his countrymen. The exception that proves the rule?