This is where things start to get really interesting.
The two tanks on the left are the FCM 2C and FCM F1. They may seem familiar and for a good reason - they were featured in Halloween gamemode in 2017, as Stein (FCM 2C) and Franken (FCM F1). These tanks also have been teased multiple times back in 2011-2012, first as tech tree tanks and then as premiums. I don't think non-skinned HD models have been seen before, though. However, it's not too surprising they modeled the actual tanks first before modelling the Halloween skins for them. With that and as we have seen them before multiple times anyway, they are not that special.
However, the two tanks on the right are something else. The tank on the left is FCM 1A, a predecessor of the FCM 2C, and the tank on the right is AMX Tracteur C (1939), a competing design of a super-heavy tank that eventually lost to the FCM F1. A good thing to note that just like with the T23 AT, neither of these models have been never ever seen before in any form. However, what makes them even more interesting is that back in 2016, when the 2nd French heavy line was planned (which is what we have had for some time now), there was actually some talk that this line was originally meant to be a full line from tier 2 to tier 10, not just minibranch like what we have now. The tier 2-7 would have been super-heavy tanks like these 4 tanks shown above. However, as the super-heavies ended up being problematic (basically, they were tested around when the O-I Exp and O-I were really problematic, and these tanks are pretty much like if Japanese heavies and TOG were fused together, so you can imagine how hard they would be to balance correctly), so they were scrapped and that's how we ended up having a minibranch just at higher tiers like we have now. With FCM 1A and Tracteur C having renders makes me think that FCM 2C and FCM F1 models were actually originally meant for the line, not for the Halloween mode. However, as WG scrapped the super-heavies, they probably ended up using the unused models in the Halloween mode.
I have no idea what's the fate of any of these 4 tanks. I would love to see them in the game, but who knows. Would not surprise me if they were scrapped altogether, or maybe they introduce a full line of them whenever they introduce the multiturret mechanism.