I was needing to know if anyone knew who to contact for having a peaceful rally at the state capitol?

I would also like any suggestions for free public places to have a rally, I live in Nashville,TN and all the "attractive" places all cost $$$. The State Capital was the only place I couls think of that was both free and public.I'm just not sure of who to contact and what the "rules" are for holding such an event. Thanks so much for any and all help :)