There is some open-source software, similar to Adobe InDesign? It would be awesome if it do exist...
I know all the others like Inkscape, Gimp, etc... but for InDesign i have none.
Could you give me one direction?
Scribus is probably the best alternative to Adobe InDesign right now. Although Inkscape can also do a quite good job. Recently I came across Lucidpress which has a web interface and it seems quite powerful desktop publishing application.
By the way, I maintain a website for open source alternatives to popular software which I update quite frequently. You can check this link for InDesign alternatives:
Try out Scribus.