Let them know that if accidents arise, they will be pursued through the French Courts.
Unlikely to make a difference with the concerned regulators.
Two reasons...
The French already give a pass to AirFrance, with all their many hull losses, and will likely do the same with other larger Euroland aircarriers.
And secondly, all the regulators have to do is point to an airline like EK, which works their pilots
far more monthly hours (some lines if time have 99:20...read about it all in the middle-eastern forum) and yet, EK has a rather good safety record.
Therefore, are Euroland pilots somehow less 'safe' than the sandpit guys?
Quite likely not, therefore, longer hours will have no effect, on safety.