Thank you for making your question to JustAnswer. My name is*****'m an Antiques Expert and I will try to help you with your particular inquiry. Please, don't hesitate to contact me any time or to make follow up questions if needed.
You have a Antique Late 19th Century Sèvres Style Porcelain Handpainted Plate. The S46 tell us it is a 1846 plate.
Can you provide a picture of the front?