Honestly? These are not IMO 'comparable' goods so it's not really possible to make an either/or decision regarding them.
Make Paris work at a slightly lower cost overall, then while you're over there scout the jewellery shops and second-hand/resale places - there are amazing stores in Paris and lots of luxe goods available. This way, you can enjoy both![]()
Solid advice.
ITA with Bitten. This is what I did on my last trip to Paris. Found a little leather bracelet at H as a keepsake of the trip

It doesn't seem like you have been wanting a specific piece of jewelry for a long time. I'd go for the trip and begin researching the perfect item. I find that research is almost half the fun of getting the piece!