At least in Germany, while it's in principle possible to sue the employee for damages, it is very difficult to succeed with that if it isn't downright sabotage. You can't force the employee to work, it quickly goes into negligence on your part if you can't handle an employee going missing, ..., so you'll probably not reach much more than the salary - and for that just terminating the contract early would be easier, either in agreement with the employee or one-sided after they stopped showing up.