I'm apologizing in advance if this was already discussed:

For example you can get a fake passport with your photo and then you take a verification - be it with uploading documents or video chat or something similar. You pass, because they verify it's you in the photo. Or do they have any other means of directly checking goverment databases? It seems highly unlikely, since I don't think for example a French company would be able to use the database of German citizens, even less for non-EU countries. So until you do something that requires the company to report you to law enforcement, you can basically "enjoy" your fake identity.

For the record - I personally never used fake documents and always do KYC for legit companies, I was just wondering how they can actually verify you.