It's incredibly bad. ~40% after first semester. 60%+ will fail the first year. That first year is basically a post high-school buffer. Netherlands have a one year gap for kids to cool off and find what motivates them. France should really adopt that.
But that too is a small minority. To be exact, in 2013, 9% of all first year students in tertiary education took a gap year. About 1/3rd of them traveled during that time, most of the rest had a job. And although the data doesn't explicitly say, it does seem like that includes those work for a few months between the end of the school year of high school (in May/June) and the start of the year at university, in September/October or in January, depending on the specifics. I'm not claiming they included everyone with a summer job, just that what is claimed to be a 'gap year' isn't really in many cases, but more a 'I have a few months time and I need to pay for my studies, let's make some money'. A far cry from the GP's suggestion that there is some formal structure to go soul searching or whatever.
Don't know about the drop out rate in first semester, but the percentage of students passing the first year can be pretty low. In medicine, I think it's aroung 10%, in maths maybe 30%.
