Do you know which business school you'll be going to in the end or are you still deciding?
I'm going to continue studying at university (The Sorbonne). In France, there are two ways that opens up after high school if you want to end with a 5 year degree : University, which is almost free (I pay something like 500 euros for one year, including insurance, sports, courses) but it has 2 major flaws : the network is almost non-existent, thus you have a more difficult time finding a job and the career development is slower. The Prépa (2 years) which is like a follow up of High school but it's difficult and requires a lot of dedication/hard work. After the Prepa, you generally enter a school (the better your grades at the competitive exam, the better the school) for 3 years. The school can cost a lot (around 10k euros/year, it can be around 15k/year for the bests), but it's an investment. The network is really huge and you will be able to have a career development faster than in university. You can enter some of these schools by taking an other competitive exam rather than the one done by those who chosed the prépa, where you do 3 years at university and 2 years at the school. I tried this way but it didn't work out this year. I might try again next year even if I "lose" 1 year.
HEC is the best business school in France, but I didn't thought I had a chance. I tried EM Lyon, which is the fourth best.