There's a suggestion that
Decathlon may register themselves in Switzerland to avoid paying French corporation tax (which is one of the highest in Europe), which seems coincidental to Macron getting involved
The fact is, Seixas looks like he might have earning potential on or near the level of Pog. As he turns from promising youngster to fully fledged threat that potential will be realised, and it's happening now.
I don't think Decathlon have the budget for him, even if they cut taxes by registering in Switzerland (they've denied this btw, but that doesn't mean all that much imo)
We're also in a period where contracts are being bought out more frequently, so he might not even last through next season