It only takes us back to where we were prior to 1 January 2021 as far as France is concerned. Other countries now require individual permission, because their exemptions only cover aircraft registered in the EU and Switzerland.
I don't think you can claim that the initial design of the DR1050 pre-dates 1955, as it received its CofA on 11/3/60. Stretching the interpretation of a regulation could be costly if an NAA, court or insurer disagrees with it.
However, as mentioned previously, I believe a factory built DR1050 is covered by Article 1.2 in the French exemption.
2. a type certificate or an individual certificate of airworthiness meeting the requirements of Annex 8 of the Chicago Convention has been issued to such an aircraft,