However, given that the Atlanta has been pulled out of sales, its not likely we may see a French Atlanta, as WG might be trying to move away from this cruiser type at the moment.
My personal guess would be to see a premium tier 6 Suffren (or possibly a tier 5 Duquesne). It avoids an outright 'clone' situation - rather than having the rate of fire of La Galissoniere, the Suffren would get a more potent alpha strike. Yet you'd still have the fragility and maneuverability native to the early French cruisers, and thus have a degree of synergy with the rest of the line as a whole.
I'd totally buy a premium tier 6 Gloire, though - in dazzle or without. (Although I confess some preference for the Georges Leygues - or the 'Gorgeous Legs', as the Americans nicknamed the ship. Just for the anticipation of hearing Jingles mangle the name in his review...)