My two cents regarding the most possible additional sports (probability to be chosen between brackets):
- Sport Climbing (9/10): fresh, cheap enough to stage, decent medal chances, domestic following (Bercy Arena packed for recent world championship), growing,
- Karate (8/10): Cheap to stage, uber high medals chances, doesn't appear like too french or too european, continuation from Tokyo 2020
- Squash (7/10): Cheap to stage and possibly set in any iconic Paris landscape, good enough medal chances, french president of the world federation (can't hurt),. Should be considered as a lock too, but it's squash and the Olympics, so you never know.
- Surfing (7/10): Decent following in the South (South) West, historical legitimy, succesfull previous events (world cup stages, recent 2017 Biarritz WC), bring some needed sexyness to the Games. Would be guaranted to be hold in 3 consecutives games (2020-2028)
- Boules sport (4/10): Biggest non olympic federation (300K members), almost guaranted medals, cheap to stage, national pastime. Could be seen as a frontrunner, but it suffers from a huge image problem (ie. it is not seen as a proper sport by most)
Outsiders: Skateboarding, Esport, Baseball, Speed Roller, Wakeboarding, Pelota basque (I wish...).
If one can't exclude anyone from the race at this point (who would have thought of skateboarding for Tokyo ?), these sports are by far the most likely to be chosen.
If anyone can read french, I've put my thoughts in a bit more articulated way (here and here)