How can I tell if Religious Tolerance is working?

In Brave New World, the Piety social policy tree has a new policy called 'Religious Tolerance'. How do I tell if my civilization is getting the benefit of Religious Tolerance and how can I tell what that bonus is?

Solution 1:

You can see what the popularity of the different religions are in a city by mousing over the city, and you can see what the effect should be by looking up that religion's Pantheon belief in the religion overview.

I've not seen the benefit in practise yet (I've got Religious Tolerance but the Pantheons of the relevant religions affect resources that I don't have near my cities).