[FREE] Sang-Froid: Tales of Werewolves [GOG]

Claim on its game page
Edit: There might be regional issues for some people, where it would require payment with real money and that exact amount would then be refunded to your GOG wallet. It was completely free for me though - no money involved whatsoever! It's also possible that the region thing is just a bug and it will get fixed soon.

It's also permanently free on Steam, but the annoying part there is that it doesn't stay in your game list, if it's not installed (like any other Free-to-Play game).