Often, marriages are mostly arranged. The young man and woman might get a veto, if it wasn’t too important. (Princesses did not get a veto.)
But, even if young people are allowed to find a partner more organically, it was usually among a selected set of partners, with strong parental involvement.
One reason for this was simply to get young people married (especially young women), before they got into any trouble.
https://blog.exitgroup.us/p/57-peg-on-the-french-aristocracys
Cornerstone 