Corporations understand and fear only 2 things.

Money. Control.

Either the fine should be high enough to alert investors and ensure that they make the company change its ways..

Or

The govt. should provisionally or in a timebound manner take a seat or two on the board.

Let the govt. Do this for a few companies, and every otger company will fall in line.

Corporations must be treated as children of the country they are born in. Sure, they become big, earn money for the govt. and are essentially independent. But if the kid goes naughty, a watchful eye and a rap on the knuckles is how you teach manners.