Kim Kardashian Back to Wearing Giant Diamonds, But Only for Halloween

Kim Kardashian gave the appearance she's going back on her word to swear off flashy jewelry in public, but it was nothing but a trick ... TMZ has learned.

Kim was wearing a couple of diamond rings over the weekend as part of her Cher costume at George Clooney's and Rande Gerber's Casamigos party. Seemed odd because she promised to tone down the bling after the Paris robbery.

Thing is ... those rings weren't even close to the real McCoy. Our Kardashian sources tell us Kim was, appropriately for Halloween, wearing nothing but costume jewelry.

Word. Kept.