Punctuation: Parenthesis and brackets

Parenthesis

They are used to give additional details to the lector. Those indications are never essentials.

Le RMI (Revenu Minimum d'Insertion) a été augmenté.

Other signes exists with a different role.

Brackets [...] are used to cut a citation or do an intervention into it.

Ils sont venus dire bonjour [ndlr: en français dans le texte] à leur grand-mère.

Brackets {...} are mainly used in schema.

All parenthesis, [] and {} are also used in mathematics but this is another story...