Do I have a Real Pierre-Auguste Renoir "Bal du Moulin de la Galette" (1876)?

I found a painting in my house. I know it's real because I can feel the dry paint texture. It looks exactly like Renoir's Bal du Moulin de la Galette. I have not measured it. How do I know if it's really Renoir's or some copycat? If it's real, it's probably worth millions. How much is a fake worth?