Hunch. Edouard Philippe refused the joint primary again on 6 and 7 November, and no party has yet signed up to organise one without him.
The joint primary market resolves on the official statements of Les Républicains, Renaissance and Horizons: YES if by 17 April 2027, 11:59 pm New York time, Les Républicains and at least one of Renaissance or Horizons announce together, by a party decision or a signed agreement, a primary to pick one candidate that all of them will back. Calls, talks and agreement in principle do not count, whether the vote is later held does not matter, and France 24 and Politico Europe are the backups.
We looked for cases where parties of one French camp, the left or the centre and right, had a joint primary on the table before a presidential election. We found five such times since 2011, four on the left and one on the centre and right. The Socialist vote of 2011 was the first open vote of its kind in modern France. (The Guardian; The Guardian; BBC; Politico Europe; Le Monde)