Which country has the highest percentage of the population that has a favorable attitude toward Jews? According to this study, it's France! That's especially remarkable, because (a) most French Jews are relative newcomers, having emigrated from Algeria and Morrocco in the mid-1950s; and (b) France has a large immigrant Muslim population, and, anecdotally, a large percentage of these Muslims seem hostile to Jews.
The interesting question is, if the French are so tolerant of Jews, why has the French government been so unable to make French Jews feel welcome and secure in the face of hostility largely emanating from the immigrant population? Thousands of French Jews have moved to Israel, and many more have purchased an "insurance" home there.