Make sure they're good at math, and have good grades in high-school so they can get selected to a good "prépa". Make sure they don't slack off in prépa.
I kind of slacked off when I was in post secondary school, I didn't go to "classe prépa" but did a DUT because I was bored of studies, still ended up afterwards in an engineering school after my DUT because my parents kind of pushed me to contest for an entry. I ended up even more bored, fell in love with a girl I met that was living in another country, dropped from the engineering school after the first year, moved abroad to join her, applied there for a job, got it at first interview. Being motivated in a work environment (compared to a more meaningless to me educationnal one), I quickly climbed the echelons to be considered an "engineer" in the industry meaning, without having an actual engineering degree. I did so during the few years it takes someone to finish engineering/grandes écoles and find an actual job in France.
I learned that in many places outside of France having a few years more work experience and verifiable credentials is actually more valuable than a nice degree when applying for a job being 25 and that at 35 nobody cares anymore what degree you got in the first place.
[1] I am taking the assumption that your kids will or have already obtained french nationality and a european passport.
- Make them good at science, i.e., Maths and Physics.
- Get them into a decent high school, e.g., Henri 4 or Louis Le Grand in Paris.
- Hope they have good grades and manage to get into a good preparatory class [1], e.g., Henri 4, Louis Le Grand in Paris, or Hoche and Sainte-Geneniève in Versailles.
- Make sure they don't slack off, and hope they get into a good engineer school, e.g., Ecole Polytechnique, Ecole des Mines, Ecole Nationale des Ponts et Chaussés, CentraleSupelec.
(Lists are not exhaustive)
If they manage to get into one of these schools, they will most likely end up not have any difficulty to find a somewhat well-paid job in France.
Very often, when a kid is good enough its school main teacher will mention the possibility of going to a prépa: it's good for a school reputation when they can send kids to prépas.
For sure it's better when the parents are already in the known, but it wasn't the case for me and it was not a show stopper. There's plenty of public information and the importance of "grandes écoles" in France is not a secret.
When I talk about these paths, I mostly mean prepas and grande écoles, but that doesn't mean I recommend them.
Yeah you're set for life if you succeed there, but the student suicide rate in those schools is also astonishingly high because of the pressure/competition.
If I were you, I'd just teach my kids to code, learn, build stuff, sell stuff, and use AI correctly. IMO school is an outdated concept, in any country.