What's the Name of That Book??? discussion

The author is probably male, and the book isn't recent. I read it in french, and it was not set in the USA but in Paris I believe, so it might be french. The main character embarks in a journey with his friends to go to a safer place.

I remember a scene , where they all have to get tetanus shots since in the future no one has them anymore. Also everyone keeps their dead relatives in their house , frozen.

Spoiler
In the end, the main character, a man, creates a world where men have many wives since the male population has decreased significantly. One day, when he is old, a man comes to him , and explains to him the invention of power through vapour. He presents a train, which the main character tries to destroy because he does not want to go back to how things were before energy disappeared. He dies.
Thank you !

Could it be Ashes, Ashes by René Barjavel?
Published in 1943; original title is "Ravage".
From Wikipedia:
Ravage présente le naufrage d'une société mature, dans laquelle, un jour, l'électricité vient à disparaître et plus aucune machine ne peut fonctionner. Les habitants, anéantis par la soudaineté de la catastrophe, sombrent dans le chaos, privés d'eau courante, de lumière et de moyens de déplacement. Un étudiant en chimie agricole, François Deschamps, décide avec quelques autres personnes, de quitter Paris, mégalopole de vingt-cinq millions d'habitants, en proie au chaos et aux flammes pour retrouver son village d'enfance en Provence. Il espère pouvoir y reprendre une vie normale mais paysanne… Le chemin est cependant long et difficile, pour ceux qui n'ont jamais connu autre chose que le confort qu'offrent la technologie et la science.

Mai wrote: "Could it be Ashes, Ashes by René Barjavel?
Published in 1943; original title is "Ravage".
From Wikipedia:
Ravage présente le naufrage d'une société mature, dans laqu..."

Yes it is, thank you so much ! you saved my day !