Hello fellows,
I guess I shouldn't have run reload(sys) and sys.setdefaultencoding functions as suggested in StackOverFlow forums (link), as I was facing Unicode encoding issues and print commands sending back errors when running my script.
Now, the ArcMap Python console doesn't provide neither autocompletion nor print output 
I could solve that problem by running a new instance of ArcMap with a blank project, but I'd like to know what went wrong with the Py console and if it would have been possible to fix it (by resetting?).
Thank you in advance for your help,
Have a good day or night, wherever you are.
- Yann