It seems, that this game is affected by the CEG DRM issue #753

Same here, how can I check logs for more info?

Find "user_settings.sample.py" and rename to "user_settings.py".If use Proton beta file is located in -steamapps/common/Proton 3.7 Beta/

Still a problem in Proton 6.3-5
steam-65930.log

Tried latest Proton Experimental with the latest Steam Beta CEG Build, and it still doesn't launch:
steam-65930.log

It's not working for me either with Steam Beta + Experimental. But I don't even get a proper log file (not runtime container related).
steam-65930.log

TheBureauXcomDeclassified.tar.gz
Logs for both launch options. Apparently JC2 is also a CEG game and at least that eventually launched for me minimized.
Supposedly the "old" method of people running this game on proton didn't require any extra things to be installed into the prefix, so the crashing issue is probably still CEG related.

Per Pierre currently when you fail to launch a CEG game or update prefix you need to use Steam to verify game files. This will give you a new fresh original exe. Then when you start proton experimental it will try again to patch the exe against your account. (that is what CEG does)

I have gotten the game to work now. The intro video also played and I could load up a game save near the end of the game ok. So appears to work 100% although I didn't test controller.

Currently you need to switch Proton Experimental to the "bleeding-edge" beta. Then set the following launch options for the game.
PROTON_NO_FSYNC=1 PROTON_NO_ESYNC=1 %command%
Then in steam re-validate the game files then launch it. Launch is kinda slow but it works. :+1:
Esync or Fsync may actually work with CEG but I didn't test.

I confirm, I was also able to run the game by changing to the proton of the game to Experimental, then on the proton experimental library entry settings choosing the beta branch for bleeding edge, then going to The Bureau library entry properties local files tab and clicking on the verify button once, then launching the game. However, if I don't use the variables PROTON_NO_ESYNC=1 PROTON_NO_FSYNC=1 on the launch parameters, game gets stuck on launching using 100% of all cores (killed it after 15 minutes this way).

After I deleted the prefix, I was able to get a proper log. However, even when I disable esync and fsync, the game doesn't start. The icon appears for a fraction of a second in the panel and then crashes. Doesn't matter if I chose DX11 or not.

steam-65930.log

steam-65930.log
@NoXPhasma but have you tried all the ritual procedure I described above? Uploading my log with the successful run of the game for you to compare.

@Patola No I didn't. I wasn't aware that there is a bleeding egde beta, I thought you were talking about experimental.

I retried with bleeding egde and can confirm that it works with that and esync/fsync disabled.

steam-65930.log

With the latest stable steam client and Proton 6.3-8 the game now load, but it start minimized and when I try to maximize it, the game crash. I have to kill it with alt+F4.
steam-65930.log

Runs fine for me with Proton 7.0-1, Mesa 21.3.5, kernel 5.16.10.