Musk, 51, who bought Twitter for $44billion, last year earned the top spot on the Forbes World Billionaires list, which reckoned he had a net worth of $216bn.
CNN reported that Arnault was able to overthrow Musk in the annual list after his net worth grew more than $50bn to $211bn, as Musk's net worth slumped to $180bn, $39bn less than it was last year, thanks to the purchase of Twitter which was funded by Tesla shares.
Forbes said: "Musk has mostly tweeted himself out of the top spot on the ranks."
However, Musk's SpaceX valuation increased from $13bn to $140bn in just the past year.
Still, that proved to not be enough to compete with Arnault, 74, who had a "banner year" in 2022 due to record-high profits at his companies.