The answer to this question is always the same. If you are unsure wear a suit, if their dress code is smart casual then remove the tie but frankly I would probably still wear a tie. I've worked in both environments in many different companies, sometimes setting the dress code and I've never been concerned with a person turning up for an interview in a suit in a smart casual environment, which is often an argument I see on here. If you are met by people in jeans and t-shirt then make a comment about your suit, such as "hope you don't mind me wearing a suit for my first meeting, I felt it both appropriate and respectful and a sign of how important this role is to me" or suchlike. It's easy to make a suit casual and business casual for many is a suit without a tie.