Sorry, new here (well, sort of, anyways) and I don't know exactly what you're referring to with "real consequences". I've played many tabletop and LARP games, from great to 'ugh', which threw around the words "mature" and "real consequences". It's just that there's a long list of things that could fall under that description so I'm a little... Cautious? I have no idea what you mean, exactly, so none of these questions are accusations. Far from it! But not asking a few of these has led to some unpleasant surprises in the past (as you can tell by the questions themselves...

).
To my experience the kinda standard consequences of 3.5 are things like losing money, losing items, losing social status or membership in a group, loss of title or wealth, public humiliation, being arrested (almost always with trial and the punishments ranging from imprisonment to execution but all being pretty humane), exile (even if it's just from their favourite tavern) and of course all the usual consequences of 3.5 combat like temporary injury, death, or capture for ransom or ritual sacrifice or the like. So very "dramatic" consequences appropriate to a fantasy story.
But can you elaborate a bit on what you mean? Considering the title are you going with consequences as large-scale realm-affecting political changes? Or on a bit smaller scale will they affect the city/Empire in a significant way? Is it more that such consequences are personal and can make (or break) a political career and greatly affect the character's options or connections? What about family and friends, could they be threatened or affected in some way? Are some of these consequences physical, like permanent injury or scarring, or maybe some sort of magically created change in the character? Is death, pretty much the ultimate consequence, a real possibility outside of actual combat? Will some of these consequences involve being beholden to other characters or NPCs -- through social, political or physical pressure or even controlled by magic -- to the degree that the character is forced to do unpleasant things against their will (or even to lose a will of their own)? Finally,
and a reminder that all of this is far more a list of surprises people have randomly sprung on me in the past than anything I actually expect from you or this game, is significant pain and suffering such as psychological or physical torture or similar things a possibility?
I feel pretty terrible to ask most of these but the alternative is just so much worse...

Sorry if I've offended.
I am honestly interested and I hope this all doesn't make me seem picky or like a creep or something. Hope you have a good day!