All you have to do to claim your free copy of Far Cry 3 is by visiting its dedicated giveaway page, and claim it using the button. Alternatively, if you already have Ubisoft Connect installed on your PC, you can claim the game from there instead.
As far as games go, Far Cry 3 is pretty old by, being nearly a decade old. And you’ll probably see this most evidently on the graphics department. But since the series has used a similar formula for basically all its entries, things should still hold up gameplay wise. Besides, getting to listen to the infamous explanation of the definition of insanity is probably worth giving the game a revisit even if you’ve completed it before. Far Cry 3 is free to claim and keep until 11 September, though the time at which the offer ends is quite all over the place. To avoid having to deal with that, it’s probably better if you claim it as soon as you can. (Source: Ubisoft)