They both started about a year ago with a huge budget for ads online, on TV, on radio, on billboards, and in cinemas. They haven’t really talked about their decision (they never do). They lost a lot of market share to other supermarkets and especially to the heavily-advertising Lidl. Surely the new managers played an important role in that decision. In other countries they always advertised.

I know they’ve experimented for a while, but I don’t think Nord launched a major ad campaign until recently.

Supermarktblog documents these changes quite well, IMO.

https://www.supermarktblog.com/2017/10/02/aldi-nord-in-renov...

The Aldi Nord campaign launched last year. I remember because I'm amazed by the campaign's bad typography whenever I see one of the posters in a shop.