The main effect that I can see is to counteract the PS's "vote utile" propaganda; so, in 2007, the Green and Communist candidates would have done a lot better, and Royal correspondingly worse; but Royal would have gone through to the second round, because I can't see many electors from eliminated candidates going to Bayrou.

Likewise, the system would probably encourage the natural tendency of the mainstream right to run two candidates, since they wouldn't have to worry so much about being eliminated by the FN.

So it's all positive for the presidentials.

_{It is rightly acknowledged that people of faith have no monopoly of virtue - Queen Elizabeth II}