Here is a link to the site selling the arm.
I am sure you know them being in Germanyicon.

Fusil de sport Suédois M63 (Version Bon Ã* très bon) de - Armes longues & réglementaires - Collection & réglementaires - Armes - boutique en ligne Frankonia.fr

With the new firearms classifications in Franceicon 6.5 X 55 is now a civilian round and can be bought with only a declaration and no authorization.

303 and 8 X 57 etc are also civilian rounds along with many others,
only about 4/5 rounds are classed as military needing permission to own 5.56, 223, 12.7, 50 Cal, and Russianicon rounds, so the arms fall into the civilian or millinery classes.
It just became a whole lot easier to own mill surplus in France this month.