The West and North coasts of France cover a huge area so I’m not sure where you are headed.! I was in Brittany a few weeks ago and fished the river Odet estuary close to Benodet. Predictably it was stuffed with mullet but I did manage a few schoolies on surface lures and spoke to a German fly fisherman who had taken a few decent bass of up to 50cms sight fishing in the various offshoot tidal creeks with a crab imitation. Whenever I’m in France I always buy the monthly French sea angling magazines (they are excellent by the way, with far more useful advice in my opinion than Sea Angler but you do of course need to be able to understand French) however I can confirm that there are always plenty of articles that cover lure fishing for bass and other species, so tactics and lures that work in the U.K. will be fine in France and of course there are more bass over there because the water is warmer. Any estuaries in Brittany would be productive and of course the numerous rock marks of that Department. Much of the West coast south of Brittany comprises open Atlantic surf beaches so perhaps not so productive with lures but interspersed are plenty of rocky areas and of course the islands of Oleron or the Ile de Re are both fantastic for bass as is the Gulf of Morbihan in Brittany. Hope this helps. Good luck!