It's all identity politics. Obama won because the blacks, browns, yellows, reds, feminazis, malcontents, gays, Jews, communists, atheists, environuts & America-haters look at him & say, "He's one of us." They harbor a deep hatred for what they see as traditional WASP America, as they believe it's unjust & unsophisticated.
In France (and most Euro-Socialist utopias) the socialists appeal to those who also hold onto a hatred of America and/or anything representive of traditional culture or "pro-white-Christian-males". Listen to their campaigns. If you don't vote for them then you're a lap-dog for American hegemony. They use that hate to maintain their political machines. Their victories have nothing to do with actual fiscal/monetary policy.