Seeking to become the first reigning champions since Brazil in 1998 to reach the World Cup final, France faced a Morocco side who had not conceded a single goal to an opposing player at the 2022 World Cup so far.
However, Theo Hernandez took just five minutes to break that resilient defensive streak, volleying home acrobatically at the far post after Kylian Mbappe's effort was blocked.
Hernandez came into the starting lineup in the opening stages of the tournament after his brother Lucas Hernandez suffered a torn ACL in their maiden match against Australia, and he spared a thought for his relative after helping Les Bleus reach the showpiece event.
"It's incredible. Playing two finals in a row is incredible. We did a great job, it was tough. The final against Argentina, we know it's going to be a great match, we're going to work hard to win this final," Hernandez told TF1.
"I have a great thought for my brother, I hope he will be there. It's incredible, I'm going to enjoy it with my family, all the players, and the coach too."
Despite losing all of Noussair Mazraoui, Romain Saiss and Nayef Aguerd - who initially recovered from their injuries before coming off one by one - Morocco piled the pressure on France towards the end of the first half and start of the second.
However, Walid Regragui's side lacked a killer instinct in the final third, and the tie was put to bed in the 79th minute by Kolo Muani, who tapped home at the back post following Mbappe's blocked attempt.
Kolo Muani's goal after 44 seconds marked the third-quickest strike by a World Cup substitute in history, and the Eintracht Frankfurt man affirmed that he was living a dream after sending France through to the final, where they will tackle Argentina on Sunday.
"A childhood dream, I'm still in my dream. We can be proud of ourselves. We were strong defensively and we scored the second goal to kill the game," Kolo Muani added.
"I don't realize, it's a sick thing. I hope we will go very, very far. A final cannot be played, it has to be won. We will approach the match with desire and determination."
Deschamps's ranks were hit by illness before the match, as Adrien Rabiot and Dayot Upamecano had to be replaced by Youssouf Fofana and Ibrahima Konate, but the latter produced a magnificent showing at the back.
Meanwhile, Fofana admitted that stepping into Rabiot's shoes was not easy, but he remains "hungry" to help France go all the way, adding: "It was not easy to replace Adrien Rabiot.
"Since the start of the World Cup, he was in a rush. To reach his level, it's hard. But with the support of the whole team, it gives us did pretty well.
"It's crazy, we don't have time to realize yet, our families will do it for us. There is this last match on Sunday, we are going to celebrate it, while remaining lucid.
"Sunday, there is a final, it's not nothing, against a big team from Argentina, solid from the start. It will be a big chunk. There is no easy match, to win a World Cup, you have to eat big, and you are hungry."
France are now aiming to become only the third team in history to win back-to-back World Cups, following in the footsteps of Brazil and Italy, while Morocco prepare to Saturday's third-placed playoff with Croatia.