Quick summary in light of new events. Yesterday a bill was voted in the national assembly which stipulated that the 75% tax extends to any company, etc. affiliated with a french federation. AS Monaco is the only fiscal entity in this situation . Yet today the government organized a new vote to void the bill. The bill is out.
As Rybolovlev had said months ago that he could simply leave if the tax was implemented, the most likely scenario is that upon hearing about the bill, Rybo picked up his phone and told the government he would leave immediately, and the government backed off because it makes no sense to lose Monaco's indirect contributions (TV rights, UEFA coefficient) for the sake of a bill that means nothing without Monaco.
I fail to see another explanation but I would like to be wrong. This would be yet another hilarious humiliation for the government, especially considering it was predictable.
EDIT: if this is true the whole situation has been horribly managed by Hollande and his administration. There were several ways to try to prevent this situation, but no measures were taken.