I thought this was some youth speak for getting engaged in Paris.
So I Google'd it.

The Essentials on The Paris Gold Ring Scam:
Where: People try to pull this scam in all the major tourist areas. I’ve read about it happening near the Louvre, the Eiffel Tower, The Jardin de Tuileries, and countless other places.
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How it Goes Down: This is traditionally not, as Rand has assumed, a pickpocketing scam (though I don’t rule out the idea that it could be used for that). A man or woman “finds” a ring on the ground. They pick it up, and ask if it’s yours. Even if you say no, they press it upon you, occasionally with the excuse that it’s “against their religion to wear jewelry.” (I’m pretty sure that’s only true for the Amish.) As you leave with the ring, they mention that 1.) they’re hungry and broke or 2.) that it would be nice to be compensated for the ring they just gave you. You give them a few euros, and leave with your ring – which turns out to be made of brass and utterly worthless.
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How to Avoid it: Just keep walking. Don’t stop, don’t take the ring, and don’t engage in a conversation (this is incredibly easy to do if you speak virtually no French). As long as you shake your head knowingly and give a firm NO, you should be okay. If someone reaches for you, don’t hesitate to pull your limbs away. As always, if you feel threatened, make some noise and get loud to draw attention.
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Related Scams: The other notable Paris scam is perpetrated by the bracelet guys near the Sacre Coeur. And pickpocketing is such a problem in Paris that the US embassy actually has a whole page written about it.
http://www.everywhereist.com/the-paris-gold-ring-scam/Pikeys!