If a company makes an agreement with a freelancer, and adds to the contract that no material/information may be used outside of working with the company how solid is the agreement?

If it is found that the freelancer has used material from the company for another purpose without the knowledge of the comany what can be done in real terms?

I am specifically looking at training, which is I believe a difficult one.

Does anyone have any samples of such agreements that they have used in the past?

Any “tales” that may help prior to entering into such an agreement?

Thank you
debbee dale