A300 Captain reported DG cargo was loaded on wrong aircraft during preflight. DG cargo that was meant for a different destination was removed prior to departure.

Narrative

During preflight; the DG paperwork was delivered to the cockpit as normal. The top pages were the typical Aircraft DG Manifest copies that indicated 'No DG Onboard.' I picked up the top pages; reviewed the flight number line and began to sign them. First Officer (FO) noticed that the envelope (still laying on the center console) had additional pages in it. Normally; with 'No DG' we wouldn't expect any additional pages other than the two copies of the Aircraft DG Manifest. I looked at the Aircraft DG Position Summary briefly and we agreed it probably was inadvertently brought to the wrong aircraft as it had ZZZ listed as the destination. If we had any Inaccessible Dangerous Goods aboard it needed to be listed on the manifest as Integrated Drive Generator; so I asked the FO to check with the Ramp Agent to verify it wasn't our paperwork. When the Ramp Agent inquired; we found out a pallet of DG was in fact loaded in position 6R of our aircraft. My understanding is pallets DG must be loaded in the front of the aircraft forward of any Accessible Dangerous Goods containers anyway. The Ramp Agent returned and informed us they would need to download the DG pallet; which they did. I'm not sure where the mix-up occurred; but there seems to be more that one issue as it relates to this incident. Additionally; this was a great catch by FO and worthy of recognition. Inadvertent loading of DG on incorrect aircraft; in an inappropriate position. Review and investigate where the breakdown of DG procedures occurred.