If you are wondering about how long a summer vacation for a French student is, and how they spend it. I might know something about it.
Until high school French student officially have holiday between June 30th and beginning of September (mostly on the first Tuesday or Wednesday of September because teachers start school before students so they have to go on Monday or Tuesday before students).
Mostly for those students who don’t have exam, school ends around June 15th (to let free space for those who have exam (in Collège you have Brevet des Collège (when you’re 14/15 years old) and in Lycée you have high school degree (at 16/17 years old you have French exam and at 17/18 years old you have all the other classes (maths, sciences etc).
For these students (because you’re not allowed to work before you turn 16) they go to summer camps or daily summer camps (or just hang out with their friends, go to visit their family) or go on holiday with their parents (or friends parents sometimes). Mostly students start to work around the age of 18 because nobody want to hire underage people.
For university students mostly there are between 2 and 4 months holiday (between may and September). Most of them have summer jobs (a lot of students like to work as youth leader in summer camps because you can be hired even if you are only 17 years old or do typically summer jobs (rescue worker at a swimming pool, tourism industry or in factories (very usual) etc). They use that money to finance their studies.
Sometimes for those whose parents can pay they spend time abroad for foreign language classes or work abroad and learn the foreign language at the same time (but it’s less usual).
That’s all I know about summer vacation for a French student. Hope this will help.