I did some research (i.e., a google search) and apparently the EU is banning the use of conventional cages for egg production starting in 2012. Granted, producers can still use "enriched cages," (from what I can gather, a cage big enough to fit 60 hens) but this still seems to me a step in the right direction.
From what I can gather, other member nations are already implementing the regs or passing stricter regs, so I would think the likelihood of being able to get "conventional cage-free" eggs is greater in France than say the US, and that alone would play a significant part in the superiority of French supermarket eggs to American supermarket eggs. (An example I pulled is that the Netherlands, 40% of egg producers use conventional cages while 90% of American producer uses these cages, and apparently the Netherlands are the #1 egg exporter in the EU).
From what I can gather, other member nations are already implementing the regs or passing stricter regs, so I would think the likelihood of being able to get "conventional cage-free" eggs is greater in France than say the US, and that alone would play a significant part in the superiority of French supermarket eggs to American supermarket eggs. (An example I pulled is that the Netherlands, 40% of egg producers use conventional cages while 90% of American producer uses these cages, and apparently the Netherlands are the #1 egg exporter in the EU).