very simple : french system is litteraly a piece of s... according to a moral position : I mean there two collateral systeme : one classical with primary school to university : for mass people ! and another one for minority of favored children of french oligarchy ( mosthly from our capital : Parisian people !) that's systeme of grandes écoles ( big schools) this is administration school as ENA, commercial as HEC or some other enginiering school, all of them in Paris, of course ! you have to know that there are principally two "denominational" school : public and catholic but all of them have public financing. In each french distric ther are a kind of governor who represent the french state ( in fact in reel life that's only the french president who decide of everything because french parliament and government have a simply of consulting, not decisional ! that's presidential system) so this "governor is "recteur d'accadémie" : he decided of everything in his area despite some feew year this ich area whose give money for Lycée ! not yet university which are still completely depend of Paris. Lycée currently positioning after collège( 10 to 14 years old) and before university ( generally at 18 years old). The problem of Lycée is the large time of studying and inflation of subject of studying : this is the famous french concept of "savoir encyclopédique" superficial studying in every subject : quantity before quality ! you should be surprise to see numerous ( like 30 people in classroom for one teacher !) and not really conversation but monolog of teacher with very passive kid ! french kid have to learn like parrot ! finnaly you have to know that the most prestigious Lycée in France were of course both located in Paris : Louis le grand and Henry IV Lycée ! generaly, if you wanted to have a great social position in france : you must to get school in very restricted area named : "le quartier Latin" all big and prestigious school are located here in this upper parisian area ! so.....good luck !

I'm gonna give some more details to your question at the end of this mail, but before I must say that I completely disagree with erwan...

Indeed there are 2 parallel school systems for higher education (after the Baccalauréats, the french equivalent to the german Abitur and similar exam to the english A-levels) apart from professional training, the universities and the grandes écoles... And yes that's right there's a large difference of level between those 2. But that is normal, since there is officially no selection allowed in the 1st year of university, while you have to get through a 2 year (very) selective curriculum (prépa) leading to a national competitive exam to enter the grandes écoles.
And no this curriculum is not reserved to the upper class children or parisians. Since I've been through this curriculum myself (and I'm not rich nor Parisian) I can tell you that everyone has his chance, since only the best and the most motivated students are offered a place, no matter who they are and where they come from... and let me tell you that you'd be surprised to see the diversity of social backgrounds you can find in such classes... the only problem is that you have to work twice as much as in university, which makes those curriculums repulsive for many students.
And no need to pretend it's completely out of price, since it is relatively easy to get a sponsor if you've had good grades (or to lend money without interests), plus I shall add that (with a sponsor) all exam costs can be paid with about 200€ (depending on which school you apply for). One last thing to notice is that at the end of my 5year engineering curriculum (all tuition fees included + prépa exam costs) I have paid less than the tuition fee for a single year of university in England.
Oh and by the way, I think it's time you knew that the huge majority of grandes écoles are located outside Paris.

Secondly, during the 6 years I've spent in the lycée, I've never been in a classroom with 30 other pupils, so I think that's not to generalize. And anyway, I really don't see what's the point since whenever you go to university you can reach up to 100 students or more for a single teacher, which is not really a problem to learn what you have to (from my experience).
Now ,concerning the "french concept of savoir encyclopédique superficial studying in every subject", well that's also not completely true to my mind.
At the end of the "collège" (around 14), there are 2 possibilities, either you go on apprenticeship in a shop or a company (you then leave school), or you go to the lycée. In that case you are to choose between 3 different types of curriculums: professional (really few theory, lots of practical experiments), litterature arts and "human sciences"(main subjects are philosophy, foreign languages (and french), music, economics etc... depending on the curriculum) and science and technology (mostly maths chemistry, physics, biology or industrial sciences)
Once you've chosen what type of subject interest you most, you are taught a bit of everything in that general area until the Baccalauréat. And that is normal since the real aim of the lycée isn't to provide specialist skills in a certain field for professional purposes (or direct application), but to prepare yourself for the higher education curriculums where you are to choose your final speciality. Furthermore, this general teaching, as bad as it may seem to erwan, allows you not to look like a complete idiot when you have to talk about something that is not included into your "specialist skills".

And finally, a little comment about "and not really conversation but monolog of teacher with very passive kid!"... How can there be a conversation when the pupils are supposed to be taught something they don't know about? and if by your sentence you mean that pupils can not ask anything, well that clearly shows that you must have been a bit too passive at school... The reason why you had to go to school every day is exactly so that you could learn and be able to ask the teacher what you did not understand IN THE SAME TIME... Else, then no doubt that all teachers would have already been replaced by books (a lot cheaper)...

Ok concerning the question below is what I can tell you from now, that would be nice however if you could tell us what you didn't understand. If you have any question do not hesitate to contact me.

At the end of the "collège" (around 14), there are 2 possibilities, either you go on apprenticeship in a shop or a company (you then leave school), or you go to the lycée. In that case you are to choose between 3 different types of curriculums: professional (really few theory, lots of practical experiments), litterature arts and "human sciences"(main subjects are philosophy, foreign languages (and french), music, economics etc... depending on the curriculum) and science and technology (mostly maths chemistry, physics, biology or industrial sciences)
Once you've chosen what type of subject interest you most, you are taught a bit of everything in that general area until the Baccalauréat. And that is normal since the real aim of the lycée isn't to provide specialist skills in a certain field for professional purposes (or direct application), but to prepare yourself for the higher education curriculums where you are to choose your final speciality

Thanks a lot for your help