Reworked answer based on new info; and a couple of quick edits subsequently -
What Happened to your Fedora Repos?
Did you edit out the fedora repos from your dnf repolist outputs?
Because you don't appear to have them...
And maybe lets confirm you are running fedora 23 :) cat /etc/redhat-release
Assuming you are truly missing them, do the following, otherwise jump ahead to the 'At least we have fedora repos' section
dnf install ftp://126.96.36.199/linux/fedora/linux/releases/23/Everything/x86_64/os/Packages/f/fedora-repos-23-1.noarch.rpm
# make sure they are enabled
dnf config-manager --set-enabled fedora updates updates-testing
dnf clean all
# Optional, potentially large update, but I highly recommend it.
If you got a large update, particularly if the kernel, systemd, dnf / yum / rpm were updated then reboot before contuining:
At Least We Have Fedora Repos Now
The following commands will remove all of the rpmfusion repos and reinstall the latest version. Barring any errors on route, we should then be able to enable them appropriately.
If you get failures similar to those you received before:
file /etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-fedora from install of rpmfusion-free-release-22-1.noarch conflicts with file from package rpmfusion-free-release-23-0.1.noarch
at any point, stop, and move right to the section on removing GPG keys from RPM, located at the bottom of this post.
Hopefully you don't have to do that it. It's not pleasant.
One caveat - I don't have any more fedora 23 machines; just F24, so I tested this code on one of those. Shouldn't be an issue, and I note a couple spots where it lead to a bit of uncertainty.
Run all commands as root. If at any point an uninstall command results in numerous 'dependent' packages also being designed for uninstallation, do not continue - that shouldn't happen.
# clean up dnf just because
dnf clean all
# pull together a list of all installed rpmfusion packages
rpmflst=$(rpm -qa | grep rpmfusion)
# for a sanity check, review that output; we're going to uninstall them all
#now remove - only click 'y' if it looks reasonable
dnf remove $rpmflst
# Double check for any stragglers
# Delete any .repo files (or mv them somewhere like ~/ to be safe) EXCEPT these EDIT - was 3, now 4 - forgot google:
# install 'free'
dnf install http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-23.noarch.rpm
# install 'not-free'
dnf install http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-23.noarch.rpm
# The first repo should be the only one needed for vlc, but we will enable a couple others (for depdendencies) as rpmfusion is harmless (I couldn't test this as vlc is in the rawhide repo for F24 beta)
dnf config-manager --set-enabled rpmfusion-free-updates-testing rpmfusion-free rpmfusion-free-updates-testing rpmfusion-nonfree rpmfusion-nonfree-updates rpmfusion-nonfree-updates-testing
# Some of those enables could fail - if they are empty, etc. For that type of error keep on going
# tidy up
dnf clean all
# Download metadata (optional - its a check of the config without involving an install)
# assuming you've had no GPG errors, try installing vlc now
dnf install vlc
GPG Conflict Error Resolution
Basically we need to just delete the GPG keys that report conflicts. There is a clear guide at the link below, and since this isn't the topic of your question, and I'm sick of typing, I'll just point you to it
Once the offending GPG key is removed, you should be able to retry the step that failed and continue from there.
If you subsequently get an error such as "missing GPG key for repo XYZ", then edit the repository file (I can't find CLI option that persists), as follows:
# Find the file that contains the offending repo config (e.g. rpmfusion-free-updates-testing)
Find the line where gpgcheck=1 and change to gpgcheck=0
Now you should be able to continue on.