They're called Divisions (Open, Limited, L10, Production, Single Stack and Revolver); once you shoot enough Classifiers, you'll be classified as D, C, B, A, M, or GM.
The CZ75 is a perfect pistol for the Production division although its also legal (but not optimal) in Limited, L10 and Open as well.
In Production you must start with your CZ hammer down and break the first shot in DA. This means your frame safety model must be decocked manually by pulling the trigger while holding the hammer and lowering it to rest. You can start cocked and locked in Limited, L10 or Open, but not Production.
With some polishing and springs you will not be held back by your 75B, it's a very competitive platform.
IDPA has a similar division, but I'm not familiar.