Geoffroy,
That's an admirable ambition, however, I think in the current climate in Australia your aim for 3 months as a ground handler may not be achievable.
The security side of things and the imminent changes to criminal history checks and the like may be too big a hurdle for you to overcome for 3 months employment.
Is there any chance of a company in France arranging a work exhange programme here for you? You may have a better chance of securing something that way.
Those jobs here are keenly contested, particularly in the major airlines.
Don't mean to rain on your parade, but I really think it may not be possible to do what you would like. I am very happy on the other hand to proven totally wrong!
TV