According to a little news blurb from EWTN, France in 2006 joined the unwed countries club. More than half of all children born in France in 2006 were born out of wedlock. The article also listed Sweden as having a 55% illegitimacy rate, Great Britain at 42%, and Poland at 15%.
If these were the examples to compare to, that might very well mean that France is ranked 2 in Europe (the World) A quick (read: lazy) search online did not yield anything interesting to confirm that statement. Didn't France use to be a Catholic country? What happened there?