French privacy law is very strict.
However it was known in France that the two boxers were banned previously for a medical reason cos it happened outside France and french law wouldn't and couldn't stop reporting of a ban. So in was publicly known in France.
Discussion about the nature of that ban would be allowed in France but not the individual personal details if they were made public within France.
It can't cover if it was revealed outside France. Only the reporting of that within France.
If publication is outside France (eg twitter) it raises questions about twitter and liability.
It becomes an issue of American Freedom of speech versus French Privacy law and which takes superiority (and where!) and what the implications of that are.
It then becomes about the US and France in terms of enforcement and enforceability and who, if anyone, is personally responsible.
Would Elon Musk be arrested if he visited France is a more interesting question. Followed by what would Elon do if that happened.
Personally I think taking on Musk on what essentially his hill to die on (even though DSDs are not the same as Trans - the issue of legality to participate due to an F in your passport rather than biology and science unites the issue somewhat), is something of a 'brave' move.
I suspect Musk would rather give up on all support for Tesla in France than capitulate.
If this battle happened then individual boxers at the centre of that, become small fry, and unlikely to be protected from online harassment outside France. Which seems to defeat the point.
Unless of course it's not about privacy at all and it's really about gaming the system for a nice big fat pay out.