Here is a non-exhaustive list of websites which could be helpful in your research into upper secondary education and higher education choices:
ONISEP (National Office of Information on Teaching and Professions)
National Portal for Higher Education Admissions (APB)
CIDJ (Centre of Information and Documentation for Young People)
Académie de Paris Rectorate website
Ministry of National Education
Ministry of Higher Education and Research
Euroguidance, for guidance, studying and training in Europe
For studying in the UK: check out EducationUK or UCAS
For studying in the US: check out Education USA
Professions website created by the Ile de France Regional Council
Centre for Study and Research on Qualifications website
Websites of universities and higher education schools also provide information about subjects taught, admissions procedures, study content and future careers.