Hey everybody,
thanks for the quick replies and the suggestions! I didn't post my renders, because I didn't have them at the time of writing.
I will do this now, together with my current renders.
Also it was quite busy at work, so I didn't have time to reply myself.
I already tried putting color in the reflection slot, but since the material has to reflect almost as a mirror, it seems to loose a lot of it's
color depending on the hdri map that I'm using. So if I use a really blue sky it will render blue (camera 7) but when I use another hdri with a lower sun, I loose all color and detail in the facade (Camera 13). So I would have liked a material like the sunglasses that would remain blue no matter the environment.
I did indeed put the refraction to black and I used fog color as a way to color my translucent glass planes (since they have thickness).
Since I yesterday had to show the current state of the renders to our client I now used a VraycarpaintMtl with a blue base color, 1.0 reflection and 1.0 glossiness. This seemed to keep its color better, and they kind of liked it. But what I'm noticing now is that at parts that get low lighting it gets real dark. So I think that there probably still is a better way to get to this material.
I will look into the suggested coated material next. It sounds great. I didn't find it yet, but a search on google brought up VrayBlendMtl, so I assume that is what you meant?
These are my latest renders:
Thanks for the help!