Compare between Argentina squad than France I think prefer with France have completed team and all position dominance by young player, different with Argentina I think just have Lionel Messi only and other position dominance by senior and less than with young player on Argentina squad. Some France player played on top team like Karim Benzema and Aurélien Tchouaméni playing Real Madrid, Mbappe and Presnel Kimpembe for PSG and many other position their player plating on top team. Maybe Argetina have little different between regular player and substitute not playing on competitive league.
If we check deep facts about all teams and their possible players then surely I am feeling France is moth lethal team in this world cup with have full ability to defend their title because they have too many quality players for all departments and these players are already doing good job in their clubs, and we can call them cream of Europe because of their strong play and quality.
With this comparison there is no competition with Argentina which is mostly depending on Messi and others are also good but have no enough quality like France and this is going to be the biggest difference between these teams here Brazil is also having few good players but comparison they are also not good enough like European teams which are currently good and having better quality for winning.