French as well as other Roman languages differentiate within the personal pronouns between the connected and the unconnected. Up to now we have seen the connected personal pronouns, that indicate the object a verb is referring to.
la lui donne. I give it to him.
The unconnected personal pronouns have a different function. They are used when a preposition come in. In English the object form of the personal pronouns are used:
Object form of the personal pronoun
They talk about
They got it from
They work against
They work because of
In French something different appears, the unconnected personal pronouns. They have an own personal pronoun to be put after a preposition:
fais pour toi.
I do it because of you.
not: Je le fait pour te.
Following we have an overview of unconnected personal pronouns. They come always in, whenever a preposition is used:
Unconnected personal pronouns
Je le fais pour
Je le donne à *
Il est allé sans
Elle est partie sans
Here we come back to the two possibilities of forming the indirect object, once with a preposition and the unconnected personal pronoun: Je le donne à moi (toi / lui / elle/ nous / vous / eux) once with the personal pronoun in indirect form as we have seen before here:
= Je me (te / nous / vous ) le (lui / leur) donne