Wait, so if I own a steel company and I fire a salesperson, I can’t go into the emails they sent from the computer I purchased for them to do negotiations with,

Wait, so if I own a steel company and I fire a salesperson, I can’t go into the emails they sent from the computer I purchased for them to do negotiations with, to retrieve information about clients? If that’s so, I’m quite shocked. How does this play out in courts? Does an employer in Germany have to sue an employee in order to access such information?