Try nail polish remover if it's only a small amount. Try paint suppliers or
this if you need a lot.
when buying nail varnish remover, be warned that some are "acetone free" which obviously isn't any good. I also recommend the "sniff test" (tm) to check you are getting reasonably strong acetone not mainly water - but I did get funny looks from the Boots guy when I did this.
It is also worth noting that if take car to France you can load up with proper solvents, concentrated acids and the like at the hypermarche as they are hard to get for social domestic and leisure use in Uk: elf & safety gorn maad I tell you