Le Pen said the name change "closes a chapter in the history of our national movement which opened a little more than 45 years ago".
The new chapter "will be no less glorious", she declared.
Party activists voted 81 percent in favour of the new name, with a 53 percent turnout.
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In a nod to the 48 percent of members who opposed a rebranding in a poll last year, the party kept its distinctive flame logo, which Le Pen's father and party founder Jean-Marie Le Pen copied from the neofascist Italian Social Movement, one of his main inspirations.
"The National Front has become adult ... its nature has changed," Marine Le Pen told French television after announcing the rebrand plan in March. "It has gone from a party primarily of protest in its youth, then an opposition party to a party of government."
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Observers say Le Pen is aiming to draw voters who back her conservative, anti-immigrant and eurosceptic agenda but who might have been turned off by her father's controversial views, which earned him expulsion from the party two years ago.
Marine had already kept the Le Pen name off her campaign posters last year and her niece Marion Maréchal, seen as a rising right-wing star despite her declaration that she has retired from politics, has stopped using the Le Pen name.
But the party has been in the doldrums since last year's presidential election, when she it to the second round but failed to win the support her supporters had predicted after what was widely regarded as a disastrous performance in the final TV debate with Emmanuel Macron.
Jean-Marie Le Pen issued a statement saying the name change was "treason" and "shameful negation of the party's identity".
"Nothing good can come of abadoning the name, neither for the movement nor for French people. Only political rivals and competitors will get mileage out of this treason," he concluded.