In my company in france Each month give a amont of day so we don't earn 25 vacation days at the end of acquisition year.

It means that each month, we earn 2.08 vacation day (25 / 12month) during the all acquisition period, max to 25 day at the end of acquisition period.

day earned can be taken before end of acquisition period

I don't manage to reflect that king of behavior with Projeqtor, I mean for exemple

just say that I start to work 1st june ... end of june I will have 2.08 day earn that I can take in july if I want to.
so if I look at leave count, they should increase each month by two day and I should see "+2days" each month...

Is there a way to describe this "monthly day earn" to projeqtor across the acquisition period ? and not only a global 25day in 12 months ???

ofc.. special earn (like seniority earn) is only calculated at the end of acuqistion period (1 june - 31 may )