Just go the confirmation in writing, after asking why the conditions they referred to only concern delays:

"You are correct that the conditions specifically mention delays rather than pushing flights forward. However, based on our understanding of AirFrance's policy, they do indeed allow for some flexibility in adjusting flight times. For long-haul flights, they can move departure times by up to 5 hours, and for short-haul flights by up to 3 hours, before offering rebooking options to passengers."

For me, this marks a new low for what was once (in my opinion) the best carrier in Europe.