Yes I accept that an airline would dead leg an aircraft if it were going to somewhere not in its route structure for maintenance, but you would never ever send an aircraft off down route knowing planned base maintenance was due before it was scheduled back to base. Which is what AF suggested they were doing.
The check cycles are flying hour, flight cycle, landings or calendar life controlled so its not difficult to plan an input at the right time.
The situation I can think of when an aircraft had to be brought home empty was when it had a defect, temporary repair for example or ferried home with an engine shut down, that was outside the dispatch manual limits therefore precluding the carriage of passengers.

Richard