It obvious to everyone except Hollande that if you inflict a punitive tax on the rich (75%) then they will simply leave the country and take their wealth with them.
It has never worked to inflict punitive taxes on the rich as they will simply vote with their feet and now France is suffering due to this stupid policy.
I do agree that all sectors of society need to pay their way but in most countries income tax banding means that the rich will already being more since a salary of say, £90000 taxed at 40% will pay more tax than a salary of £50000 taxed at 40%. Unearned wealth is another matter but those paying tax (via payroll taxes on a salary) already pay more.