Granted we haven't got any hard information but the exit polling is too much in accordance with the pre-election polls - which didn't predict the large turnout.
So either the banileus (sp?) is voting for Sakozy or the polling models are wrong.
Uncharitably - who knows? It's a good point. Perhaps they're just re-quoting the polls and not doing proper exit vote counting at all. (Although I wouldn't guess that was very likely.)
On the other hand, if it turns-out I'm right I promise to be insufferable for the next 2 weeks. ;-)