I think you might get a perfunctory discount coupon and maybe some points but for a 45 min flight, I don't think it merits too much effort for "compensation". There isn't necessarily a points difference depending on the AE "fare" you originally booked. Now if you got downgraded on YUL-CDG....that's another story. I don't know if you fly AC often but this is par for the course for them and we've been discussing this since the beginning of FT in threads usually about FAs in J. It does bring up nostalgia for me though about the time LH downgraded me from O class to I class YYZ-FRA and I eventually got 4000 euro. Good ol' days !