Actually it's a MiG-27. But it's strange because the GDR never recieved those.
To be honest, this is actually the trainer variant MiG-23UB, easily known by the shorter radome and the cockpit with two seats.
The MiG-27 doesn't have the rounded nose present in the MiG-23 fighter variants since it does lack a proper radar, and because of that, the MiG-27 does have a "platypus"-like nose, like the MiG-23 bomber variants.