Succession by representation takes place when a descendant becomes a successor in the place of an ascendant (father or mother) who has died or is declared unworthy of inheriting.
In the direct line, representation takes place ad infinitum in the descendants of the deceased: children, grandchildren, great-grandchildren, and so on.
In the privileged collateral line, representation is permitted only in favour of the children of the deceased’s brothers and sisters.
Example
Joseph has two sons, Paul and Robert. Paul has a daughter, Mary.
Paul died in 2010. Joseph then dies in 2015.
Successors
Joseph’s direct successors are his sons, Paul and Robert.
Since Paul has died, Mary becomes a successor in his place, as his representant.