Tin, tin, TBT, tributyltin, same poison
Exactly, these are “old-fashioned” antifoulings with TBT (tributyltin), very effective but also extremely toxic over the long term. Many countries have banned them to protect coral reefs and other creatures in mooring areas (among other reasons).
In more lax countries, it’s still for sale.
It should be checked, but it seems to me that it’s banned on all hulls in French waters, or simply on all French hulls (probably rarely checked). Additionally, it requires extreme precautions during maintenance (the “less toxic” ones are already potent poisons that you need to protect yourself from).
Personally, I wouldn’t use it, but I think a previous owner applied it to my hull, which would explain the residual effectiveness even though it should have been removed long ago.