Fine the investors. Everyone who owned a share when the violation occurred takes a lick.
If you go after c-levels, what will happen is they'll devise some sort of time deferred compensation avoids the penalties you want to impose. The board needs a CEO after all, and CEOs are reluctant to run a company if they know they'll just have their paycheck confiscated.
A fine to the investor is literally taking money out of their pocket. Before they receive the dividend check. Even if it nets the same to them in the long run, it will feel different. It will be true punishment rather than reduced reward at a later date.
Corporations are made of people, and can by large multinationals, or small mom and pop operations with a few tens of people (or less). Should someone that has a company that runs a few ice cream shops in town go to jail because of actions of people under them? Because it's not like it's always going to be something that was condones or expected from management, and while I'm okay with monetary damages that don't aim to dismantle the company entirely even if management didn't really know what's going on (that's maybe a good way to make them care and pay attention), I'm not okay with sending them to jail because of mismanagement.
Not only is that unfair, it would have a huge chilling factor on entrepreneurs. And not just the startup kind, the people that want to open a restaurant or run a small business.
And to fully put this in context, this is under an article about booking.com paying slowly. You think jail time is appropriate for that? What if they're having cashflow problems? If they aren't and it's intentional, how do you distinguish this from that?
For punishing corporations (for whatever legal reason) I would rather see a percentage of c-suite compensation for a time period (including end of year bonuses) confiscated, maybe along with a fine based on profit (so stock values are hit as well, so that both can't be used to avoid penalties and also to signal to the market it's a bad idea).
The problem with fining a company is that often you hurt a lot of the lower ranked employees that had no power and often no knowledge of the problems, and usually weren't involved in any way, sometimes to the point where they lose their jobs if the company is hurting to a much larger degree than the people running the company do, which is why punishing corporations is sometimes hard.
We need to incentivize and punish the people that actually decide the problematic policies and actions and not those that just happen to be in proximity and/or are linked financially, to the degree that we can (obviously it's hard and no perfect solution exists).