Thanks for your input. Since we are talking here about real guns i think that this wouldn´t work under German gun laws, which are VERY restrictive. Here you open a can of worms.
another option for a display piece, many wartime M1 Garands were, like their M1903A3 predecessors, converted in the 1950s for use as drill/display pieces for use in parades or in drill practice with ROTC units across the U.S.
Those rifles have been certified de-milled and incapable of loading or discharging a live round of ammunition by modifications made at the arsenal level.
As non-functional replicas, they might be a bit (read that VERY slightly), easier to obtain within the boundaries of non-U.S. territories.
There will be a number of difficulties that I believe would require an inordinate amount of time, paperwork, applications and approvals, tax stamps, customs fees, and other various time and monetary delays, to getting a working world war 2 era firearm transferred for non-governmental ownership and use, from a civilian owner to a civilian buyer.
There are some international firearms dealers who do specialize in handling such transactions, and they can do the legwork and paperwork, for a price in their fees, but also provide the service at likely, a better probability for success. I would begin with IMI Industries, and with SAARCO, Inc. They are the two most well known for international functional wartime antique firearm sales to civilians - and both companies hold many international firearm dealership licenses to conduct such business.