if you run the game fullscreen at a non-native resolution your cursor/aiming circle will be off centered. I had this same issue and found pressing alt+enter would toggle fullscreen after adjusting the FOV slider and it worked fine.

The aiming circle gets inaccurate with any other FOV which is a shame, because I feel claustrophobic with the normal FOV

Wehzy I don't know if you still care at this point, but for anyone else in the future this is how I got it to work. IDK if its all necessary, but it working for me and these are the steps I took.

1. Put in you JC3 folder. For me it was D:\SteamLibrary\steamapps\common\Just Cause 3

2. Make sure JC3 is running

3. Run the file as administrator (right click and select run as admin)

Thats how I got it to work for me so I hope this helps someone :)

Does not work. Everytime i launch the exe i get an error "couldn't find the just cause 3.exe"

People who claim that vanilla fov in JC3 is fine, are delusional.
Even in Red Faction: Guerrilla (which this game is, but on Mars) you can set fov in-game to 85.

Any way to get this to work when running the game on linux (using proton)?

Wow thank you , is so much better now with an ultrawide monitor .

This is cool but I'm fine with the normal FOV (but if I do set it up it goes to max, like with Minecraft and Borderlands and literally every other game with an FOV option)

It is very helpful, thanks : )

The FOV in this game isn't fine at all. It sickens me how the camera is so close to the character.