These are some great explanations, and I appreciate the Francophone sensibility on this matter, but as an American, I can only think to myself, "Wow, that seems like political correctness run amock." Here in the US, we went through a period during the “culture wars”, where certain people and businesses wanted to push "Happy Holidays" as the "proper" greeting this time of year, but we the people pushed back. Now, if I say "Merry Christmas", but you're Jewish, and respond "Happy Hanukkah", we both smile and go our ways without offense. The same happens if I tell you "Merry Christmas", but you respond "Happy Holidays" because of secular or atheist views. The same thing applies to Festivus, Solstice or the African-American holiday Kwanzaa, all celebrated this time of year, or Muslim holidays observed later in the year. The fact that someone is considerate enough to wish you well for whatever holiday they are celebrating, whether secular or religious, should be enough, and just because we aren't celebrating the same way, or even the same holiday, doesn't give me the right to correct your choice of well wishes, or vice versa. There's no need to take offense at someone's goodwill. Maybe it's a uniquely American perspective, but regardless of where I am, I will keep wishing others a “Merry Christmas", "Joyeux Noel", “Fröhliche Weihnachten" and “Feliz Natal.”

I agree with Denis on the fact that you say "Joyeux Noel" in private with your relatives or friends. In public, we would rather say "Bonnes fêtes".

Well actually, that's a good question. We usually use "Joyeux Noël" for xMas but we are a laic country and the separation between church and state (law of 1905) is very important for us, so "bonnes fêtes" is more generic and doesn't hurt anyone (laic and other religion). Moreover, "bonnes fêtes" is for both xMas and New Year. That's why it's plural. At work for instance, or more generally in public, I use "Bonnes fêtes" and not "Joyeux Noël". In private, in family, I say "Joyeux Noel".

Probabbly you met with a radical atheist. In France, Benelux countries and Scandinavian countries sometimes it happens.

I am pretty surprised, as a French Canadian, to hear that. While people do say « Joyeux Noël », it doesn't have as much a religious tone as before. Most people would never say « Bonnes fêtes » (to talk about Holidays), but they would rather say « Joyeuses fêtes ». We learn something everyday I guess. Happy Holidays ;-)