cos’è la flétrissure in questo contesto???

Being branded (with hot irons) or tatooed (against your will) because you’re a criminal of some sorts.
Check out definition 2 on here if you can read French [https://www.cnrtl.fr/definition/fl%C3%A9trissure](https://www.cnrtl.fr/definition/fl%C3%A9trissure)