It is AIR CANADA (codesharing with LH)
Personally, I am voting for AC.
I fly usually YUL-FRA-PRG, due to codesharing buy the ticket from LH and enjoy the transatlantic flight on AC aircraft (A300 in winter, B767-300 in summer) and then finish the trip on LH on whatever aircraft they use at the moment, usually A319/320/321 or B737.