The candidate made his surprise announcement during a televised TV discussion programme on Monday evening.
After accidentally announcing that the tax would be for those earning "one million euros a month," he corrected himself to say "one million euros a year."
"I've seen the incredible increases in salaries of company bosses - two million euros a year on average," he said. "How can we accept that?"
"What I don't like is indecent wealth," he said "These salaries that have nothing to do with talent, intelligence or effort."
France currently has a top tax rate of 41 percent for incomes over €500,000, although this can increase up to 45 percent in certain cases.
Hollande has already said he plans to impose a 45 percent rate on those earning more than €150,000 a year.
As well as this France has a wealth tax on those with assets over €800,000.
Speaking at an agricultural show on Tuesday, Hollande defended the proposed measure.
"This sends a signal of social cohesion," he said. "There is an effort to be made and an act of patriotism. It is patriotic to accept to pay additional taxes to get the country back on track."
The announcement seemed to take even his own party by surprise.
A member of Hollande's campaign team, charged with financial issues, seemed not to know about the proposal when asked by TV channel France 2.
"You're asking me about something that I haven't yet heard about myself," said Jérôme Cahuzac.
Government ministers were quick to condemn the proposal.
Budget minister and government spokeswoman Valérie Pécresse criticised the "tax inflation" of Hollande's programme.
Hollande "invents a new tax every week without ever proposing the smallest saving," she said.