hay guys,
I need some help with my front lower facia of my 323i 2000.
I seems that I have a large area where the paint doesn't shine or it looks to be dull seems likes a oxidation, but not sure. How can I can I make like the rest of the front bumper or make it shine .:dunno

Difficult to understand what you are saying, but it could be many reasons.

Could be that it got sand blasted, the clear coat could have failed, it could just be scratched up, you may just need to wax it, or switch waxes if there is excess build up, truthfully it is hard to tell.

If you try everyting and wax is not working, and it just does not want to shine up even after rubbing compound then try a polish. Try using less abrasive first and work your way up if needed. A polish should be able to bring it back to a high shine if applied by hand with lots of patience, or with a machine (caution needs to be taken though).