I don't know of many games that are truly Python based. Because the drawing libraries are usually C++ it often makes sense to use Python as a scripting layer on top of an engine framework. And, this has been done regularly.

Just to answer the OP directly.

NO, you cannot make a commercial, 3D FPS/RPG/SHOOTER/etc, IN Python.

But, you CAN totally make it WITH Python.

What does that mean. It means that you can program the game in python, and use modules that calls on lower language (like C, or even C++) to run the game for you.

Panda3D is one example of this.

-Exo

Just to answer the OP directly.

NO, you cannot make a commercial, 3D FPS/RPG/SHOOTER/etc, IN Python.

But, you CAN totally make it WITH Python.

What does that mean. It means that you can program the game in python, and use modules that calls on lower language (like C, or even C++) to run the game for you.

Panda3D is one example of this.

-Exo

If you take that logic to its conclusion, then you can't make a AAA game 'IN' C++, because somewhere down the line it inevitably uses a module that was written in C or even assembly.

Surely the main question is, "can I write a professional, commercial game where the only language I use during development is Python?" and the answer is most certainly yes. Writing the next Call of Duty is unlikely but there are many games that don't require that sort of performance and which can feasibly be sold.

I have found a python code in Battlefield 2.

The game has been developed in C++ rather, but Python has been added as a scripting subsytem.