There is a product i used as a painter called "Goof Off" (not to be confused with goo gone) and as the name suggests, it's a paint removal product. Go to any paint-selling place, and they can refer you to such a product
note a couple of things
1) It might not remove the paint, like any paint removal product, it kinda depends on the situation
2) Test it in an inconspicuous area first, as it may actually damage the surface along with removing, or perhaps not even removing the paint.
3) Goof OFf has a very strong odor, and is a very thin liquid. So be forewarned
Also see if you can gently scratch off hte paint. I don't know how long it's been there, but if it's recent you might have some luck that way.