Purest French?

I am an American student, and my summer assignment is to write a huge essay. I want to write about the French culture somehow, but because I am still learning about French, I don't know much about the culture. I was researching topics and came across this website.

I was scanning through some posts looking for possible topics when I noticed someone mentioned that the purest French is spoken in the Loire. Is this true? Why? Where is the worst French spoken... possibly Quebec? Why does the quality of the French spoken even matter?

I really think I could make a great essay out of this idea. I would really love French and American feedback.

Lauren