Originally, this was only on the Steam Workshop, but I got a request to put it here, so here it is. The following description is directly from the Steam Workshop. The current version is 1.8:
"The vanilla game is a little economically unrealistic, so this attempts to fix that. Some things were not made completely realistic for the purposes of balance. I did a lot of testing, but I am not perfect, so please let me know if you find any bugs or balance issues. Also, if you have any requests, feel free to ask me and, if it wouldn’t detract too much from challenge or fun-factor, I’ll do my best to incorporate them into the game.
If you like this mod, please check out my South Korea mod and give me feedback. Thanks!
There have been many small changes to the game, but here are the major ones:
v1.8:
+Added Affirmative Action
-Broke the link between Road Building and Car Usage. More roads doesn't necessarily mean more cars.
*Reverted Race Discrimination Act to normal
v1.7:
+Enterprise Investment Scheme now affects innovation
-Removed the Libertarian Party (It didn't crash the game, but it didn't work either.)
*Fixed a bug where high Education yielded an increase in Racial Tension.
*Lessened the effect of State Health Service on Innovation (I might remove this altogether in the future, but I'd like to see how it works like this before I remove it.)
v1.6:
+Added the Libertarian Party (I've tested this but I'm unsure if it will work. I'll remove it if it causes problems.)
+Co2 Emissions now affect The Environment
-Broke the link between GDP and Co2 Emissions; GDP increases car usage which increases Co2 emissions already, and a high GDP might come about as a result of environmentally-friendly businesses, so this link didn't make sense.
*Reduced GDP's effect on Tobacco Usage
*Reduced GDP's effect on Alcohol Consumption
*Increased the reduction of Private Healthcare on Drug Addiction
*Reduced GDP's effect on Immigration
v1.5:
+Re-added the link between GDP and Cyber Warfare, but it's less intense than it was before.
+Science Funding and the Space Program now increase innovation.
+New icon for Innovation!
-Broke the link between GDP and Obesity.
*State Health Service reduction of innovation is now less intense.
*Private Healthcare increase of innovation is now less intense.
*Reduced inertia for education to affect innovation.
*Fixed Corporation Tax's reduction of innovation; cancelling corporation tax is now better for innovation than simply lowering it to a certain level.
v1.2:
-Cyber Warfare is no longer linked to a high GDP (I have plans to instead link it with bad Foreign Relations).
*Private Pensions and Private Housing now slightly increase equality. However, they don't increase equality as much as they reduce equality in the vanilla game. i.e. I didn't simply flip the equations.
v1.1:
*Innovation is now not as harsh on GDP. Changed from a worst effect of -70% and best effect of +30% to a worst effect of -40% and best efftect of +60%.
v1.0:
+Added Innovation (A blue icon in Economy).
-Broke the link between GDP and the environment.
-Broke the link between the Hybrid Cars Initiative and Car Usage.
*Inheritance Tax and Corporation Tax can greatly reduce innovation, though Corporation Tax below 5% will not reduce Innovation.
*Small Business Grants and some other things (such as private industry) can increase innovation.
*Legalizing drugs now reduces crime. Decrease in crime is directly proportional to the increase in legal drug consumption.
*Legalizing prostitution now slightly reduces crime.
*Pollution Controls still help the environment, but reduce innovation.
*General Strike is not as harmful to GDP.
*Private industries are generally more effective than state-run services.
*Earnings are now dependant on other earnings (this is not trickle-down economics).
*Racial Discrimination Act now increases Racial Tension instead of reducing it (All other aspects are the same).
*High Unemployment now reduces wages.
*Reducing restrictions on handguns now decreases Violent Crime and increasing restrictions increases Violent Crime. FUTURE PLANS:
+Add Equal Pay Laws with all of the realistic economic effects.
*Further integrate innovation.
That’s all I can think of for now. Enjoy! 
P.S. I will no longer respond to any complaints about the changes I made to Handgun Laws. The gun control debate is so old that I simply won’t have it anymore. I will not change this aspect of the mod because, based on statistics, I believe the changes I have made are economically realistic. Please find something else about the mod that you think I should change, add, or remove. Thank you."
Extract realismpack.zip to your Democracy 3 folder and save a notepad document called realismpack.txt in Democracy 3\data\mods with the following text in it:
[config]
name = Economic Realism Pack v1.8
path = realismpack
guiname = Economic Realism Pack v1.8
author = Plankicorn
description = The vanilla game is a little economically unrealistic, so this attempts to fix that. Some things were not made completely realistic for the purposes of balance.
Thanks for trying out my mod, and any constructive feedback is thoroughly appreciated!
realismpack.zip (776 KB)