If you have an existing non-platinum account go here (its in german but chrome/firefox can translate for you), enter your member number and email, click the button and you get upgraded to Platinum for free.
Update: Commenter Colleen notes “…or just select “English” on the upper right pull-down menu and the translated page will appear ”
As I noted with a previous offer at the beginning of last month,
Platinum status generally requires 60 nights (or 25,000 points earned) and comes with a 100% points bonus and then at Sofitel, Pullman, and MGallery hotels: room upgrades that the rules say you specifically have to ask for, 4pm late checkout, guaranteed availability, and a welcome drink and gift.
I’ve always found it odd that A|Club elite status doesn’t get you recognition at Novotel properties, but still being Platinum which is their top tier is certainly better than a hole in the head as my grandfather used to say — especially when the status is instant and free.