Hello Norwegianguy,
If I understand correctly, you're wondering what's the path to take to become a lawyer in France, starting with just a high school diploma?
If that's the case, the first step is to make sure that your Norwegian high school diploma is recognized "as is" in France, so that you can register in a university (there may be some prior administrative process, I'm not an expert on the matter, but the university should be able to answer you on this).
Then, in order to become a lawyer, you'll need to obtain a bachelor's degree in law (3 years), and at least a 1st year of Master degree (called "Master 1"). A LL.M is only available for student who already have a bachelor's degree.
From this point, there are two differents paths :
-if you want to become a lawyer employed in a company you'll most likely have to complete your Master degree with a "Master 2" (the 5th year of legal studies) (FYI there's a lot of competition to enter the best "Master 2"), then do a few internships, and look for a job (FYI the job market in that field is quite competitive, but you should still be able to get a decent job if you've got a good and coherent resume) ;
-if you want to become a barrister/solicitor and work in a law firm, you'll need to pass the bar exam (you can apply for it once you've completed your first year of Master degree, i.e. after 4 years of studying law), with courses delivered by an "Institut d'Etudes Judiciaires" that will prepare you for the exam. If you pass the exam, you'll have to go through 18 months of bar school and internships. Also, you'll most likely need to complete your master degree, and maybe also add one year of LL.M/Business school diploma (the job market is very competitive too for solicitors).
I hope that I was clear enough, and not off topic. Feel free to ask me any precisions if needed.
LaForceMajeure
PS : On a totally unrelated note, i love Norwegian black metal, your country is awesome!! Ostenfor sol, og vestenfor maane ... Dit kommer du sent eller aldriiii ... Tiiiil verdens ende baerer deeeet!!! \m/