I thought that Renault has it different than Peugeot/Citroen. The former has common parts with Nissan and the latter with Opel (also part of PSA) and Fiat. Am I wrong?

Opel still shares no platforms with the french cars, it is all GM. The first car based on the PSA platform is planned to come out next year.

The grandland shares platform, it's actually built in the same factory than the 3008. It comes from an accord previous to the acquisition of Opel from psa

Other manufacturers don't do shared designs ?

Definitely, I didn't have a snarky intention with my comment.

I'm just honestly surprised