I dont exactly how they got those slots.
But I know it s a lot easier to get them when you fly for Air France.
In the last round of reallocation(ex Air Littoral slot), Aigle Azur got the best piece of the cake. As a matter of fact they are going to fly Air France flight numbers.
Same for Airliner, which is not a subsiduary of Air France but flies for AF.
You probably know that half of people from the Cohor (official entite allocation slots in Paris) are actually Air France staff (paid by AF and lend to the Cohor).
There is no real competition in France. You have to live with it.