How to disable change playermodels?

How do I make it were I can disable the player models in my server? I want to do this, so people won’t look like a cop as a gangster.

Assuming you are on DarkRP as you said something about gangsters and cops, go into your Config.lua and find “GM.Config.enforceplayermodel” and set it to true.

Its already on true and I can still change my player model. any other way?