LONDON (Reuters) - German media group Axel Springer is considering a sale of its affiliate marketing unit Awin, according to three people familiar with the matter, following the planned break-up its owners agreed last year. 

The group has in recent weeks invited banks to pitch for an advisory role to help sell Awin, which helps publishers promote advertisers' products, two of the people said. 

It could be worth around 400 million euros ($436 million), one of the two people said. 

The rest of the marketing unit, which includes price comparison site Idealo, is under review, a third person said. 

A spokesperson for Axel Springer declined to comment. 

The sale efforts come after German billionaire and chief executive Mathias Doepfner and private equity firm KKR, which also declined to comment, agreed a 13.5 billion euro deal to break up Axel Springer last year.

As part of the deal, Doepfner and Friede Springer, the widow of the group's founder, will take control of the media business including news titles Bild and Politico, and marketing services, which includes Awin, Idealo and Bonial.

KKR and co ( KKR )-investor Canadian pension fund CPPIB will take control of approximately 90% of the classified division, comprising jobs site StepStone and real estate ads unit Aviv. The remainder will be held by Axel Springer and the Springer family. 

The Awin sale could attract interest from private equity firms and other affiliate networks, the third person said. Founded in 2000, Awin's global affiliate network has 1,400 employees and works with more than 1 million publishers, and 30,000 advertisers. 

KKR bought a 3 billion-euro minority stake in Axel Springer in 2019, in a deal that valued the group at 6.8 billion euros.  

($1 = 0.9175 euros)