The Nokia 6 comes with a metal body design and although the front display is very reflective, the the rear side has a black matte finish. What I like about the back side is that it's almost not reflective at all. I think it has a matte color finish and it's not because that the metal itself isn't smooth and reflective. Usually a glossy back whether made of plastic, metal or glass, makes fingerprints and smudges really stand out and that is why many reviewers define those as fingerprint magnets. It might not be an issue for those of you who intend to use s protective cover case for the Nokia 6, but if you just want the Nokia 6 to look as slim as possible without any case, you at least know that the rear side isn't that prone to fingerprints.
Here's a video shot by TechDroider and you can see that when he turns the phone around, you can see that there are fingerprints, buy the look flat, not reflecting too much light.
If you want to see what a fingerprint magnet type of phone, just take a look at the Xiaomi Mi Mix which very glossy body made of ceramic.