How do you say about my sister in french?

Here's how you can say "about my sister" in French, depending on the context:

Formal:

* "En ce qui concerne ma sœur..." (This literally means "Concerning my sister...")

* "Parlant de ma sœur..." (This means "Speaking of my sister...")

Informal:

* "Pour ma sœur..." (This means "Regarding my sister...")

* "À propos de ma sœur..." (This means "About my sister...")

You could also use a more specific phrase, depending on what you want to say about your sister:

* "Ma sœur est..." (My sister is...)

* "J'aimerais vous parler de ma sœur..." (I would like to talk to you about my sister...)

* "Je pense à ma sœur..." (I am thinking about my sister...)

Remember to choose the phrase that best fits the situation and the tone you want to convey.