They may be looking at a318/319's
Where did you read this? There is not the faintest chance in hell of this. For a start the AF subsidiaries are not allowed operate anything that AF mainline do, secondly the scope clause limits subsidiaries to under 100 seats. As it is, Citujet can only book to 100 on the 110 seat -300. Thirdly, the political fallout of giving the Irish subsidiary decent aircraft, while Brit Air and Regional use C/ERJ's, would be huge. This is France remember. The fact that it would make sense to give the best aircraft to the only part of AF shorthaul that makes money is not relevent.
The eldest cityjet 146s turned 21 this year, with the rest almost there. The ARJ rumour is still about but no concrete signs as yet.
As for
This may cause the company to order A330/340
So far beyond the realm of reality there's nothing to be said.