Hey, thanks a lot for your response!
In my case it’s already a curve (I created a mesh and converted it into a curve) like you can see in my following screenshot. That’s important because I need this sharp 90 degrees angels.
I made sure that my plane is reset with Ctrl-A and my Curve modifier is after my Array modifier.
What confuses me is that in your screenshot there is the same problem that I’m facing. The plane gets a deformation when it’s duplicated along the curve.
To make it more clear, this is the result I’m looking for:
(In this screenshot its made by hand just to show what I’m looking for)