Another question following fiasco of my unrealistic "Pompidou v. Pinay v. Deffere, 1969" scenario 
Jean-Raymond Tournoux in "Le Tourment et la fatalité. Tout finit par se savoir" wrote, that before declaring his candidacy Poher tried to pressure General Marie Pierre Kœnig to became a candidate instead. Kœnig of course refused, but what, if he says "yes"?
A non-political great figure to try to gather the non-gaullist right, the centre and the moderate left ?
An interesting idea.
I don't know how Koenig would have campaigned.
But the political landscape wouldn't have been completely changed.
What is more, IIRC, Koenig was a traditional Catholic.
Most important, he was RPF deputy (even if he rallied PMF and Faure, like Chaban).
So, as Defferre was very low, Koenig wouldn't have grasped many votes here. On the contrary, in the second round, the PCF wouldn't have changed its line: "bonnet blanc et blanc bonnet". I even think that many left voters would have found it more difficult to vote for Koenig that to vote for Poher.
Overall, the results would have been very similar to RL.
Sorry...
