IOTL a far-right terrorist took a potshot at his motorcade during Bastille Day celebrations. WI he'd killed Chirac? Who would win the presidential election? (held later that year along 1969 lines)
Quite hard to say.
Le Pen would be, of course, out of question, as Front National would be seen as the inspirator of Chirac's death. Sarkozy would not have enough popularity and support from the UMP to be a serious contender. the center-right candidate would be either Alain Juppé or Edouard Balladur, although guys like François Bayrou or even Philippe Seguin may have their luck.
On the other hand, the left would probably stop being a bunch of asses and have a common candidate : it's probably the high number of left-wing candidates that prevented Jospin to have enough votes to pass the fist round. I don't see Jospin coming back, though, for he had resigned two months ago. Even it's unlikely, I think the PS would have looked for a respected, above-the-parties guy, such as Rocard or Jacques Delors. Those two would have probably made it, given that the PS government was not that impopular in 2002.
First of all, who would be Prime minister? Honestly, I'm not sure. Strauss-Kahn is a possibility. Martine Aubry another one, but it's realy hard to say for sure - Jospin never confided on what he would have done if elected.
Would a new Gaullist leader change France's stance on Iraq? (While Sarkozy did cozy up to Bush, Chirac (rightly or wrongly- he did have close ties to Saddam) did oppose the Iraq war (Of course, so did Jospin, Le Pen and the Commies...).
I'd rather go with François Hollande.
I guess Aubry or Delanoe would have taken the leadership of the Socialists.