I'm flying one leg of a 3 leg trip on Air France in September. I am going in to this assuming they will measure and weigh my carry on for the last leg of my trip which is on AF. The verbiage from the AF website states:
"The maximum dimensions of your hand baggage are: 55 x 35 x 25 cm/21.6 x 13.7 x 9.8 in. (including pockets, wheels, and handles)."
I have been so obsessed with this that I DID buy new luggage but I also wanted something that was as light as I could get it.
Is your first flight on AF or will you have transited somewhere along the line to an AF flight? How many changes do you have after the AF portion? Are you willing to chance checking your luggage this year?
If you do opt to check luggage, I'd cross pack with your travel partner.
BTW, on a FB page I'm on someone posted that at a transit in Paris AF did want her to use the sizer for her bag before she boarded. Each experience is different and you may not be questioned...or you might be.