Well, it has changed a lot, but you've got it. The Code civil articles 19 to 19-4 states that you are not French by birthright. If you were born in France, you become French at the age of 18 (automatically, no question asked) if you have lived at least 5 years (no need to continuity) in France since you're 11 (21-7 Code civil). And you can renounce to your french nationality in the 12 months after the automatic acquisition (until your 19 or the moment at which you join the military). For now, there is some shit about "path to citizenship" in the French law... but it's for adults asking the French nationality.

But, you can ask for the French nationality before, as early as the age of 13, if you lived there the 5 preceding years. The difference is the automaticity, at 18 it's automatic, before that it's on request.

And under 18, everyone has more or less the same rights, not withstanding the nationality.

In America, many of what I would call the far right are advocating a similar system whereby you aren't granted citizenship at birth if your parents are not citizens, but gain it later on in order to fight "anchor babies" - the idea being that right now, if you are "undocumented" and you have a kid on US soil, the kid is an American right away, and sure, if you are a citizen, your mom can stay and take care of you, and as part of that, your mom gains a reasonable path to citizenship. (US immigration policy seems to be centred around uniting families.)

My reading of the French law makes it look like it would solve this "problem" as the kid isn't french, so you can deport the kid and their parents. Out of curiosity, am I reading that right? that if two undocumented immigrants have a kid and the authorities deport the newborn and the parents and manage keep them out of the country until the kid is 18, the kid is not french at all, even though she was born on french soil?

You are actually right, the European take on immigration is awfully right winged when compared to American... It's due to the way these nations built themselves. US is a country of immigration, it literally constructed itself upon it. While Europe is a place of emigration, immigrants always were looked upon as strangers lurking around. But France also being a latin country, kept something of the Right of the Soil, mixed with the Right of the Blood from northern and eastern European people.

So it's quite bastard... problematic.

Your reading is quite unfortunately not totally correct. A child born or not in France is in theory undeportable, even if their parents are from Mars or undocumented (which seems to be the same to some people...). Actually, under 18 it's impossible to be undocumented... because there is no document to authorize a child to live in France, they all have naturally this right. No visa, nothing.

EXCEPT (there always a fucking horrible exception), if you came into France without requesting a Visa (that is not needed... but you must request it... go figure...) and entered France coming from another state of the European Union (thanks EU for your horrible immigration law). Then the kid can be sent back to the EU country he came from... which is free to deport the kid if the law of this country allow it. (Well except if he came into France without parents... then he is not deportable again).

But then the worse is to come. If the parents are undocumenteds... well, their kid is not deportable... but they are. It's been a long time France dealt with the "anchor babies"... and in the most hypocrite way. So the parents have a choice : Go with their children, or abandon their children... I kid you not. And I let you imagine what most of parents end up deciding... And no, the answer is not what most fox news talk show hosts would think, since they think that these parents only have those children to have documents. It's sad... but we have problems with the far right since much longer than you... the damage they've done to our law is staggering.

So the final answer is yes. A kid of undocumenteds born in France, can be deported (""""at his parents choice""""), and then he will not be able to respect the 5 years requirements, and not be French at all.

I hope the actual administration is going to change something about that... but well.. I know the won't.