Some pointers to start with:

https://en.wikipedia.org/wiki/Age_of_Enlightenment

the central doctrines [..] were individual liberty and religious tolerance in opposition to an absolute monarchy and the fixed dogmas of the Roman Catholic Church [..] along with increased questioning of religious orthodoxy.

https://en.wikipedia.org/wiki/Libert%C3%A9,_%C3%A9galit%C3%A...

The ideals of the French Revolution eventually became the underpinnings of both the US Constitution and the European and UN Declarations of Human Rights. The reason why they're called non-Christian is because they originated as a countermovement to religious doctrine.