These social media sites know their platforms are ~50% troll accounts assigned for manipulation to move policy and commercial goals (and many nations, advertising firms, and political activist groups, are engaged - not just France). But they do their best to conceal that fact so the regulation hammer doesnt come down. Facebook took down something like 2 billion fake accounts this year and twitter about half a billion (at least those are the numbers they announced). They dont get them all or anywhere close to it because its essentially impossible.
Nothing new under the Sun, only the tools have changed. Everyone has been doing this for centuries.
Why is Facebook choosing the spill the beans publicly against France now is what is probably interesting to find out.
This is of interest because of discussions regarding Russia and China using social media covertly.