For the first time in modern French history, neither major party has made it to the run-off of the presidential elections, and hence the new president won't belong to either party. Due to the terrible presidency of Hollande, the traditional splintering of the left-wing vote and Fillon's 'fake jobs' scandal, it's not only Marine Le Pen who makes it into the second round, which was more or less expected, but also Emmanuel Macron, running as a centrist with a party created on the spot.
In many ways you could say this is a good thing, forcing both of France's major parties to stop taking their power for granted and pay more attention to the many French who feel their voices aren't being heard. But Macron's background is about as elitist as they come, and considering he never held elective office before nor has much in the way of a party behind him (next month are the parliamentary elections - Macron's party may get some seats here and there but nothing remotely resembling a majority), it would be extremely challenging for him to govern in a way that really changes the status-quo in any significant way, assuming he even really wants to.
Marine Le Pen and her Front National are still not offering more than simplistic populist slogans and borderline racism; they don't deserve a chance in power, nor will they get one (and no, that's not hubris comparable to the complacency before Brexit or the American election; the polls have her down by 25 percentage points or more, that's not a margin you come back from in two weeks). But all the same, many of their voters are simply people whose voices aren't being heard and whose concerns about immigration and being left out are ignored - and looking at the immediate barrage of declarations from both left- and right-wing politicians tonight that of course they reject the FN and will vote for Macron, it doesn't look like much will change in that regard.
There's a lot of comparisons being made between Trump and Le Pen, but I don't think that's very accurate, and in fact it's unfair to both of them for different reasons (Trump's views are less borderline racist and less economically unsound than Le Pen's; but on the other hand, she is an actual politician with established principles and policies, and she can actually relate to the people she represents, not being a billionaire). But certainly the comparison holds to the extent that they represent people who feel left out of the self-congratulating consensus of the political mainstream, and want to shake things up. In that sense, Macron's victory in two weeks' time will only be a real victory if he manages to do better than his predecessors to tackle those people's concerns, despite his precarious starting position - an extremely tall order.