I don't have a lot of time for MO'L's style of management and his mouth, but, on the French one, he has an interesting line of argument - the EU has arrangements for the residence and tax treatment of ships crews, why nothing similar for air crews?? OK, I know it is a trick question, but if the EU means anything then they need to be consistent.
He will certainly push this one, it is only in the French courts so far. If he gets a reference to the EC court, which is presumably what he is playing for, then the sh1t will hit the fan, every citizen has the right to work where they want, MO'L will argue that means they can be rostered.... or the like.
There are unwritten agreements between the EU Member States not to allow questions of this kind to get to the EC Court, the countries know that the principle of free movement of labour, enshrined in the Treaties, will be the guideline for the Court, has to be.
As person I have sympathy for the French protection of workers, I certainly don't want the zero hours stuff as practised in the UK, for example. If the EU has rules and MO'L's company operates there then he has rights also.