Remapping map # to § key

remapping.md

Now for the magic. If you don't already have it, you will need to create a DefaultKeyBinding.dict file here:

~/Library/KeyBindings/DefaultKeyBinding.dict

Once you have this file, open it and add:

{
    /* Map # to § key*/
    "§" = ("insertText:", "#");
}

Save that, restart your Mac and you will be the proud owner of a new hash key!