France-wide data can help establish context, but local discussion is where you may learn which comparisons are poor ones. I’d browse the France section, then search within it by the specific town or coastal area rather than expecting one national thread to answer everything.
Is this intended as your home, a long-term rental, or something you may resell fairly soon? At 220 m², the tenant and buyer pool could be quite different from that for a more typical flat. Also, does the new build have lifts, cooling, concierge space or other shared systems? “New” does not...