The difficulty in comparing the two is how the government works in each country. Both France and the US are democracies, but they are constructed rather differently.
And how each country comes to the place of equality is very different as well. Canada, for example, came to gay marriage etc. through the courts interpreting a rather modern constitution, vs legislative changes that has happened in France or, partially, is happening in the US.
In part, I am saying that seeing how countries come to equality is interesting from both a cultural perspective (public support, will, etc) and a study of government structure.
Me? Canadian. Bit lost. Mostly harmless.