"Kyou" in Kyousuke Mamoh's name means "crazy" or "mad".
One crowd member at the races resembles Zenigata, but with a swapped palette.
The year Jirokichi of Kawakumo supposedly lived was 1850. This means that his alleged son, Théophraste Lupin, must have had Arsène when he was in his late teens or early 20s; Arsène's birth year was 1874.
Lupin pretends he's a farmer from 1850, before his alleged great great grandfather married Myléne Lupin. According to this logic, his great grandfather Théophraste was born soon after; according to the story 'The Queen's Necklace', he died in the 1870s, soon after Arsène was born, and given that Arsène's mother, Henriette D'Andresy, was in her 30s in the story, which was set in 1880, she must have been slightly older than her husband, and Théophraste must have died when he was in his early 20s.
Since what Lupin says can't always be trusted, and he was saying this to trick Mamoh, it's not known who Théophraste's parents were or when he was born.