Paving, seems like you're trying to graft American politics onto the French election and while I see your points, I don't think the categories are the same. I don't claim to know enough to contradict you but here are few points that are, to my understanding, very different from the assumptions you're making

-Jospins' underperformance in 02 was in part due to a high rate of abstention in Paris, esp among professionals , since the election was held the weekend of a school vacation (and absentee balloting is very difficult). So its not as if Jospin lost because he didn't do was well in "the rurals." And Paris is not comparable to say New York; its by no means overwhelmingly PS. Paris has strongholds for the left and the left has gained there tremendously in the last 10-15 years but the UMP and the FN both get a lot of votes in Paris and environs.

-its inaccurate to equate "the provinces" with "rural" and even more inaccurate to equate FN support with "rural" voters. Very little support for the FN in "petites communes" in fact. Political allegiance of these towns varies greatly from region to region, but almost nowhere do small towns support the FN.

-its pretty clear that Bayrou is drawing from both "right" and "left" voters but his recent surge has come a lot from center-left voters (teachers, educated professionals) and a lot from what you're calling "rural" voters.

-Royal's "base" is by no means solid, if by "base" you mean industrial working-class voters, the traditional socialist base, who more or less have abandoned the PS since the 80s, esp after the 35 hours legilsation. The FN has been pushing hard for these voters (Le Pen's "convention" in Lille sounded like a Communist rally) as has Sarkozy ("the value of work...")

-Moreover, other traditional PS constituencies -- civil servants and esp teachers -- for instance seem to be moving to Bayrou. There's actually very little natural "base" for the PS which is the problem

-Sarkozy's "base" is by no means eroding to Bayrou. Sarkoyz's "base" of support is pretty solid, which is why Sarkozy's people keep saying Bayrou is Royal's problem. They're right on that count but what they worry about is that he might finish ahead of her and be able to run as a "rassambleur," unifying left and center.

My point is only that this isn't Kerry all over again. Its something else entirely.