I can see this being both good and bad for Europe. Good in as much as its the kind of self reliance Europe needs, and America has been pressing for, and Bad in as much as Russia will be very very upset, and America will be saying "no, not like that" in a belief the more compliant AUKUS process was going to do an outcome more favourable to the US.
With a strong domestic nuclear sector, and with committed orders for a new fleet of subs, this will boost french trade, and presumably also be somewhat economically useful albiet inflationary. Jobs and enhanced position inside the European defence posture.
Meantime, the Eurofighter "lets try again" edition is falling apart, and Rafale is saying "thats ok, we've got this"
I would say the French Defence Materiel industry is pretty happy at this point, as are french construction, downstream industry, nuclear, and military lobby interests.
That's kind of what MAD is. It's also because of MAD that France signals it's intention. No point doing this in secret.
I would point out the Russians also signal intent. So, the M part of MAD is still there. Ukraine aside, there's mutuality around what they do facing european nations, mostly.
Overflights and ships straying off-track have been going on continuously since the 1950s. What changes is the intensity of reportage, not the acts themselves very much.
If you're looking for disquieting change, it's how China is postured. They've decided to be a lot more confrontational about the island chain claims, and Taiwan, and even the reach of their navy on tour around Australia and New Zealand.