You want to sue for that
I get calls from headhunters all the time. It's common in my industry.
Get over it...or else get a real problem.
According to your profile, you're a consultant....Head-hunters LOVE consultants. You should know that.
If you find this call damaging to your career, then I would suggest that you're not good at your job. Your HR
department called you and asked about it...You explained it. Big deal? If something as insignificant as that is a career-ending phone call, maybe you should
consider a career-switch.
Seriously, I doubt that you're worried about your career from this. You shouldn't be. Your manager may even realize what a valuable employee you are and even offer you some incentive to stay.
If it bothers you, I believe you should escalate the situation to their boss. Threaten legal action if you must, but really suing? Come on. There are far worse problems in the world.
Ever heard of the Stella Awards?