Well the #1 clue we'd use is the colour neutrality / white balance, but that is something that people tend to change automatically when they scan a neg or slide or print... so this is not easy.

But offhand I'd say this is quite possibly a daylight-balanced slide film. Notice how the areas illuminated by the incandescents are warm, whereas the daylight areas look more neutral, and the highlight transitions are quite fast and the shadows quite deep. So I'll say it's some standard slide film.

With a modern color neg film like the fuji 160s you'd not see so much of a warm/could contrast and you'd have probably preserved all the highlights and also more shadow detail.

And yes, there are PS filters, such as the AlienSkin package, that emulate this look. And you can also diddle with a scanner to get this look from neg film. But it's no fun!