French phrase
C'est ma faute.
Meaning
It's my fault.
When to use it
Admits that one's own action caused the problem. Often used as a direct apology without excuses.
Example dialogue
Tu as avancé ton pion de deux cases !
You moved your pawn two spaces!
Pardon. C'est ma faute. Je n'ai pas suivi la règle. On recommence ?
Sorry. It's my fault. I didn't follow the rule. Shall we start again?