Justifier belong to the 1st
group. Justifier is a common french verb.
Justifier is conjugated the same way that verbs that end in : -ier
Justifier is conjugated with auxiliary avoir
Justifier verb is
direct transitive, indirect transitive.
French verb justifier can be conjugated in the reflexive form: Se justifier
verb is a direct transitive verb, so passive voice can be used.