First and foremost, we recommend discussing this information with a lawyer. Aside from that, this website is a great tool that provides the information about the rules for different countries regarding email marketing:
http://www.dlapiperdataprotection.com/#handbook/electronic-marketing-section/c1_US/c2_CH

If you go to it and click on the 'electronic marketing' tab, the rules will be displayed for sending marketing emails to that country.