Partially correct. French Law permits rifles in ORIGINAL calibre under certain number limitations, if to be used in matches etc.
I would hardly call the Lithgow single shot target rifle a conversion of the FN FAL (we call the semi-auto military rifle an SLR, NOT FN FAL). The single shot rifle bears VERY little parts from the SLR. It's more a new made rifle than a conversion. I take it you have never fired or disassembled one?
Thankfully. When you see a No6 or a SMLE III* HT done to 7.7x54R, it makes you cry. I have seen BOTH!