As Mozilla points out, there are numerous safe browsing systems to which you can opt in — opting in being the key here — and there's nothing preventing any entity, the French government included, from creating their own software, browser extension, or DNS service for anti-fraud purposes. They don't need legislation for that, but they do need laws to force software providers to implement a non-optional, government-operated blacklist of "no-no" sites they deem unacceptable for any reason they see fit; it will absolutely not be limited to fraud alone.

France's proposal is so stupefyingly contrived, it's so obvious this is the true intention.