I work at a small startup (~30 people) and the woman that is responsible for recruiting apparently told my salary to someone while having lunch (I don't know to who).
Now my department knows that I am getting paid almost 3x than them. It's because I have far more experience (they're almost all new graduates from college). But I can already see the change in the way I'm treated.
What recourse do I have? Isn't this against the law to begin with?
That sucks. Legalities aside, you feel like your privacy's been violated, and that team dynamics have been negatively affected. That's worth asking your boss (/the founders) for a conversation about no matter what the cause.
Bring it up professionally, of course. The last thing you want is to have an incomplete understanding of what happened, and go in on a crusade. It's possible the recruiter never mentioned you by name. They may have only mentioned your title or position relative to a team, not knowing the person they were talking to (or someone connected to them) would be able to so easily identify you. The effect is the same, and that's what needs to be addressed foremost; center the conversation around that, and let analyzing cause and any needed consequences stem from that.
By being concerned the only thing that you display is that you yourself do not feel you deserve it!
The ideal thing would be to hold your mouth and not be instigated to escalate this, rather what you should do is PROVE it to them that you do deserve the 3x that you get, not simply because of your experience but because of your talent and ability!
If you are good enough they will not only accept this with grace but will respect you , however if you aren't good enough , even escalating such an issue won't win you your peers back, but just silent them momentarily!