We do have a set of advertising guidelines, which I think covers the areas you're referring to. You can read them on our site. If you go to the bottom of any page, there's a link called “terms”, and that leads you to a place that provides all of our governing documents, including our advertising policies. There is also additional information in our help centre about that.
We do have policies that restrict advertisers' ability to target based on certain sensitive characteristics—for example, based on race or ethnicity—and we limit them on that basis. There are other content-based restrictions as well on how advertising can work.