What is the procedure to report a bug/crash about a Steam game?

I've some games that crashes in Steam, but I can't find to whom I should report the bug. Should I go to the developer's page or to some obscure Steam form?

It can be both. You can't always know for sure if the crash come from Steam or the game itself. It happened to me a while ago when Amnesia A Machine For Pig wouldnt start on Steam. I contacted both the Editor and Steam support in order to get an answer (I even got the same answer from both side).

• If you have an issue with steam : Create a new ticket on Steam Support
• If you want to report to the game editor : Try here to find your game and on the steam support page (of the game) you have a link to the editor's support page or form.