Add the game to Steam as a "Non-Steam Game." You can then use Steam's Controller Input to map keyboard keys to your controller.
In Steam's controller settings, you can search for and download community-made layouts that mimic the original PS2 or Xbox button configurations. beyond-good-and-evil-gog
If the game launches in the wrong language, use the Language Setup tool under the "Additional Executables" menu in GOG GALAXY or the SettingsApplication.exe in the game folder. Add the game to Steam as a "Non-Steam Game