When I played the game for the first time I had some annoying flickering artifacts on my screen. The flickering is not game breaking, but they are pretty annoying so I started searching the web for a fix. Over time, more fixes were reported in the comments section and they have been added to the list.

So far, three options for fixing this problem have been reported.
1 - The original fix I found back in 2013
2 - The fix reported by Monkey Tommo
3 - The fix reported by DudeJazza

If one does not work, please try the others. Also, if you found another fix for the problem, please report it here together with your system specs so I can update the guide.

Good luck fixing and have fun playing Beyond Good and Evil!

I found a guide [pcgamingwiki.com] where they told me I had to disable HW Vertex Processing in the settings application.
To do this you have to launch the settings application that is inside the game folder in your steam/steamapps/common folder.
There you have to check "manual configuration" in the advanced settings tab.
In the advanced settings I disabled the HW Vertex Processing as they told me to, this fixed the flickering issue but my framerate went down from 120 fps to 20 frames per second.

Then I tried some other configurations in the settings to get that frame rate up and the thing that worked the best for me was disabling HW Vertex Processing, Multi Vertex Stream and the W Buffer. While enabling/maxing out all other settings.

When I disabled these three things my game ran a smooth 120 fps without the annoying flickering.

Launch SettingsApplication.exe in the game folder located at steam/steamapps/common.
In the advanced settings, enable manual compatibility and disable:

• HW Vertex Processing
  
• Multi Vertex Stream
  
• W Buffer

While leaving all other settings enabled or maxed out.

I hope this was useful and enjoy the game!

I ran this game on the following system: Windows 7 64x, a Nvidia GTX 560ti GPU, and an Intel i5 750 processor. However, the fix has also been reported to work for the following configurations: Windows 10 Pro, a Nvidia GTX 970 or 980 GPU, and an Intel i7 4790k or i5 4670k processor.

This solution requires changes in the NVIDIA 3D application settings. To find these settings, right-click your desktop and open the NVIDIA Control Panel. In the Control Panel, go to Manage 3D settings, and open the Program Settings Tab. The game specific options should show themselves after searching for BGaE.exe. For BGaE.exe, try the following settings:

• Antialiasing Mode = Override any application setting
  
• Maximum pre-rendered frames = 1
  
• Monitor Technology = Fixed Refresh (not available for everyone, G-Sync related)
  
• Texture Filtering - Negative LOD bias = Clamp

Next, the following options have to be set in the SettingsApplication.exe located in your local game folder. Here, in the advanced settings, try the following settings:

• disable 'Triple Buffering'
  
• disable 'Fastflip'
  
• leave rest enabled or at maximum

Thanks to ancalimon of the GoG forums and to Monkey Tommo for reporting this fix here.

Monkey Tommo ran the game on a GTX 1080 with an i7 3770k and Windows 10 x64.
This fix was also reported to work with a GTX970 and an AMD FX8350 with Windows 10 64x Pro.

According to DudeJazza, the above settings did not work, however, simply disabling anti-aliasing did solve the problem for the most part. He was using an AMD Radeon GPU and Windows 10.