Center of attention is a common expression. New Oxford American Dictionary center of attention noun a person or thing that excites everyone's interest or concern: the bride was the centre of attention.

Or do you mean 'centre of attention?' What was the context of what you heard?

Do you mean "seeker of attention?" - it means somebody who says or does things to court others' notice. "Sinner of attention" is not an expression that is commonly heard, but if I were to define it, I would say it refers to one who does sinful (evil) things in others' notice/attention, or for their attention... Not sure.