You must actually take the test and score that. It’s in addition to TOEFL and bac results. (And typically, because it’s so different from the way French students are trained, they do really badly on sat/act. The content is easy but the format is utterly foreign to the French system. )
It means you become eligible for honors scholarships and honors scholarships at some flagships, but it keeps your odds of admission to any college in the top 2% (~top 75 on Forbes list) at 3-5%, so no more than a third of your list should include such 'dream’or 'lottery ’ schools.