You are right in your assumption. § 259 requires intent. Usual interpretation is that the offender needs to know the fact that the good was somehow acquired illegally (but doesn't need to know any details). It's not enough to think of a possibility of such an action, they have to resign to the fact. (There are other obligatory characteristics that need to be fulfilled, but they are irrelevant to this discussion.)

Simply handling stolen goods is not a criminal offence in Germany.