Miraculous: Tales of Ladybug & Cat Noir - Santa Claws, on TF1 (France) / Netflix (USA)
IMDb; TV Tropes; Wikia
streaming sites: Disney+ (S2e26); Netflix

This special episode was titled "Pire Noel" in France, where it aired in December 2016, between the first and second seasons of Miraculous: Tales of Ladybug & Cat Noir. I believe I first saw it in 2025, on Disney+. Unfortunately, my review has been lost, so I'll have to watch it again sometime. Which isn't so bad, because it's a good episode.