I flew from TXL Monday and can confirm it was enforced at Terminal C.
They specifically told me that being an AF Platinum and/or flying business class didn't have any impact as those were "official rules".
My personal experience:
2 PAX, with 1 carry-on, a backpack (regular, computer size), a hand-bag, and two cushions (don't ask, but it wasn't big ones, smaller than a backpack). We would usually fly with this no issue (and no issue inbound from CDG btw). But ex-TXL, the gate agent told us it was only one piece per PAX. We tried to negotiate a bit, checked-in the carryon, did some matryoshka magic with the backpack and the handbag, and went to the security line, where we were kindly asked to go back to the check-in desk and check either the backpack or one of the cushion.
We might have been unlucky since after clearing security, we did see a couple of people with carry-on + handbag (but no carry-on + backpacks though)