1. France, like almost every other civilized nation, does not have worldwide taxation. So when French citizens move to Switzerland, Hong Kong, or the United States, they pay tax to those nations. But they’re no longer subject to French taxes on this foreign-source income. Sadly, that is not true for overseas Americans, who are subject to tax in the nations where they live AND the IRS. Their only choice, if they want to escape this punitive and unfair form of double taxation, is to give up U.S. citizenship.
2. But when Americans like Eduardo Saverin decide to surrender their passports, they are hit by punitive exit taxes. This is the type of policynormally associated with some of the world’s most odious regimes, such as Nazi Germany and the Soviet Union. France, I am told, is not perfect in this regard, but the tax treatment of people re-domiciling in another country is not nearly so onerous (especially if they go to another EU nation).