First of all, I don't know whether this is helpful for anybody. The clip is specifically made for the window I have which is, uncommon for Germany, not a “Kippfenster” (Hopper window). ;-)
However, I hope it might be at least an inspiration. The design is attached. Feel free to change it as you need it. As this was one of my first approaches to design a part in FreeCAD, I used way too many cuts for the outer shape of the actual clip. Maybe I'll upload a nicer version in the future were I merge the cuts but for now, this is it. 

The design composes of four parts:

• The actual clip
• A screw + surface area to secure the window in place
• A screw + nut to secure the exhaust hose holder
• The clamp for the exhaust hose by J. Kaiser

If you print the clip with the long, wide side on the surface, you won't need any support. I used 0.12 mm layer height of PLA. The clip and screws take roughly 2.75 hours to print while the clamp for the exhaust comes extra.

You can find the whole exhaust system for my Bambu Lab X1 Carbon in this collection.