Have you installed The Saboteur, launched it, connected a gamepad, and found that the game doesn't even see it, and you only have a keyboard and mouse as the only control option? Don't worry, there is a solution!
I faced this problem myself after buying this game, and figured out how to solve it.
And of course I will tell you how to do it ;)

The first thing you need to do is open the game's properties.


The next thing you need to do is go to the "Controller" tab and enable Steam input.


After that, save everything, and on the same page in the Library, click on the gamepad icon.


You will see the gamepad configuration window. You need to click on the "Keyboard (WASD) and Mouse" template below the current button layout.


You will see a menu with a choice of two (and possibly more) options. From there, you need to choose the Gamepad template.


Save everything.

And voila - now the game finally sees your gamepad properly, and you can play with it. Below you can see how the whole thing looks in the game.

As you can see, the gamepad is now working properly in the game, because we finally see the hints of different buttons for the XBOX gamepad. In my personal opinion, The Saboteur should be played exclusively on a gamepad, because this game is made for it (like Assassin's Creed).