Oh, I remember this espisode. In fact, there was a very interesting TV documentary about this UN crisis, where they interviewed top diplomats (Powel, Strraw, Fisher, de Villepin, but also Blix and some others). I don't remember the exact wording, but here is what happened. I suppose you will aceept the explanation, as it was made by a British diplomat?
France wanted a second resolution. The British to. The US didn't. Bush was supposed to make a speech about that. But as usual, he screwed his speech, and change a few words. The problem is this words gave the impression he was OK for a second resolution. You know how the French love to study in details everyword of declaration, it's our national sport. Well, Bush mistakes made us think he was agreeing to a second resolution. So we said to Powell we were happy with the speech. But the French position has never ever change in ANY thing ; we have always been against an intervention with only one resolution. All the French official declaration went in this way.
So when the day of the actual discussion came, big surprise on both side : the French didn't understand why the Americans no longer wanted a second resolution, and the Americans didn't understand why we didn't agree with them.
And that's how an error in a few words lead to a big misunderstanding. There was no French betrayal.
The only betrayal I can see is the decision to call off the vote 5 minutes before the meeting, and calling the press to explain how France made the vote impossible, without even telling the French ambassador first.