"I think more than ever we need to go out and vote. We can't leave our country in the hands of these people," Mbappe said at a press conference in Hamburg ahead of France's Euro 2024 quarter-final against Portugal there on Friday.
"It is really urgent. We have seen the results, they are catastrophic. I hope it changes and that everyone goes out and votes, and votes for the right people."
The second round of voting takes place on Sunday, with the National Rally (RN) hoping to win a majority of the 577 seats in France's National Assembly.
If the party achieves that, their 28-year-old leader Jordan Bardella would be set to become the country's prime minister.
Mbappe did not cite the RN during his press conference, but he did take a humorous approach to the subject during an exchange with a journalist.
When the reporter tried to make himself visible to Mbappe by pointing out that he was on the far left of the room, the player replied: "Fortunately you are not on the other side".
New polls have projected that the RN will fall short of total victory in the elections as the centre and left make local pacts aimed at thwarting the far-right's rise to power.
Mbappe has led the voices in the France team at the Euros who have spoken out against the far-right.
"This is a crucial moment in the history of our country, an unprecedented situation," Mbappe, 25, said just before France's opening match at the tournament last month.
He added that he was "against extremes and against divisive ideas".
Teammates Marcus Thuram and Jules Kounde have spoken out against the far-right too, while Aurelien Tchouameni declared himself against "extremes", like Mbappe.
The president of the French Football Federation, Philippe Diallo, this week told AFP that the organisation was happy for the players to have "freedom of expression" but that it must itself remain "neutral".
Mbappe is leaving Paris Saint-Germain to move to Spanish giants Real Madrid next season.
