And while Americans are pretty well homogenized, don't think that people here are unaware of their immigrant background. Everyone is aware of their heritage, and while they might not know any details about what it means to be Russian, or German, or Irish, and while it might not matter on a day-to-day basis whether somebody is from one background or another, people are very much aware of it and they do take it into consideration at times of marriage, for example. "Is he Irish?" or "Is she Russian?" or "What church will they go to?" are standard considerations.
I simply do not understand how you can group France and America (both U.S. and Canada) together on this point. It is one of the (few) significant differences between our backgrounds.
Everybody knows their background, but only minorities seem aware on a day-to-day basis, and viceversa, for obvious reasons. Our knowledge has surpassed our wisdom. -Charu Saxena.
France is mostly populated with people descended from families who have lived there since pre-history, is that not correct?
That is not correct. It's been an immigration country forever. Romans, Normans, all the Celts, The English later on, and, in more recent times, Russians, Poles, Germans, Italians, Iberians, Arabs, Africans, Vietnamese, etc...
Fun fact: France has the highest number of different surnames of all countries in the planet. In the long run, we're all dead. John Maynard Keynes