I saw this coming a mile away. I don't think its confirmed but wouldn't be surprised if they go ahead with it.
Unlike aviation, where development costs are high and more companies are pushed to work together.. leading to less variety and options out there..
Armored vehicles are simpler and way more companies/countries are able to produce something on their own. In addition, they're also alot easier to upgrade/update to specific needs.
We're entering a phase where the future of armor warfare is changing rapidly and we're not quite sure what it looks like yet. Its why I think we are seeing greater divergence in new armored vehicles.. from the European experimental tanks with large 130-140mm guns, and the new Chinese Type 100 with quiet electric engines, and a smaller but high velocity 105mm guns, and the Japanese and Americans looking more at lighter MBTs.. it doesn't make sense to me for countries to invest on this massive new system yet. It makes better sense to take what is currently existing and continue on with incremental updates until we have a clearer understanding of future needs.
There's also other ways French and German industries can work together. CAPINT is an example (Leopard 2 hull, French turret), and it being an incremental rather than huge leap.