The possessive pronouns are nouns that replace the possessive nouns modified by the possessive adjectives. They agree in gender and number with the noun they replace, not with the possessor.
For example:
C’est mon stylo. C’est le mien.
“le mien” in the sentence above replaces “mon stylo”. When we use the possessive pronouns, we generally want to avoid repetition or emphasize the possession of an object. Observe the following example:
Mes parents sont très stricts alors que les tiens sont très ouverts.
My parents are very strict whereas yours are very open-minded.
“les tiens” in this sentence are used to avoid repeating the word “parents”. So, instead of saying: “Mes parents sont très stricts, alors que tes parents sont très ouverts”, we replaced “tes parents” par “les tiens”.
For example:
C’est mon stylo. C’est le mien.
“le mien” in the sentence above replaces “mon stylo”. When we use the possessive pronouns, we generally want to avoid repetition or emphasize the possession of an object. Observe the following example:
Mes parents sont très stricts alors que les tiens sont très ouverts.
My parents are very strict whereas yours are very open-minded.
“les tiens” in this sentence are used to avoid repeating the word “parents”. So, instead of saying: “Mes parents sont très stricts, alors que tes parents sont très ouverts”, we replaced “tes parents” par “les tiens”.