Perhaps the scam hasn't jumped cultural / linguistic borders yet. Pig butchering scams used to be almost exclusively targeted at Chinese users until China kicked out the Triads. The Triads then set up slave camps in Myanmar and started targeting English-speaking users instead.
I wouldn't be surprised if all the book marketing scammers are one or two groups of people that just haven't thought to target French authors yet. But basically any creative endeavor in the Anglosphere has its own attendant scammer ecosystem.
Or who knows, maybe the Francosphere just doesn't have the algorithmic gatekeepers the Anglosphere has.