If the Swiss Justice Minister and the UN High Commissioner on Human Rights (based in Switzerland) are calling for it to be overturned in the European Court, there probably is considerable legal basis.
Anyway, it doesn't matter if its not in the Quran. Taking Holy Communion is not explicitly prescribed in the Bible, and banning that will necessarily have infringements on religious rights. There is no rule in the Old Testament, Talmud or Shulchan Aruch against wearing yellow armbands, but a law requiring Jews to wear armbands will necessarily have infringements on religious rights. Additionally, a law that has discriminatory impact upon a religious group is not allowed under the European Convention.