restaurants in normandy - restaurants in beynac/cazenac

I can't advise about the Périgord.

Those are my picks Normandy, roughly from W to E, from several trips over the past few years:

• if you find yourselves in the Mont St Michel area, I was simply blown away by the Littré in Avranches last September. The lunch menu was the best value French meal I had in years.
• I found pickings were a bit slim towards the D-day beaches, but I really enjoyed La Trinquette in Grandcamp-Maisy for a fish/seafood-focused dinner
• In Bayeux, Le Lion d'Or was a slight disappointment. It was not bad, but expensive for what we got considering the region.
• In Honfleur, there seem to be many good options. I visited Le Bistrot du Port and found it quite good (not 10/10 but a solid 8); reservations were essential on a Sunday lunch.
• In Rouen, La Pêcherie is an excellent seafood restaurant.
• If you visit Lyons La Forêt, I have good memories of a lunch at restaurant de la Halle on the main square
• I never tried it personally, but if you are happy to splurge a little (with menus in the upper double digits), La Table d'Elka in Varengeville is supposed to be excellent. And Varengeville is lovely!
• If you go as far north as Mers-les-Bains (not Normandy but just over the border), L'Itinérance is excellent

Otherwise, as a seafood lover, I never really had a bad meal on the coast of Normandy. A quick check at Google reviews before you go, and you should be good to go!

Curious what time of year, as seafood availability varies seasonally.

To add a few, see below. I've called out Michelin starred places with an asterisk because they're more expensive (typically) and come with a level of service the raters at Michelin seem to prefer yet some (like me) find too intrusive and fussy.

Servon: l'Auberge Sauvage*

Granville: L'Edulis or La Citadelle

Hambye: Auberge de l'Abbaye

If you want to get into the sticks, try to find Krill in La Baliene. If you can find La Baliene you'll find Krill: it's right across from the Marie (the one with a whale vertebrae in the window)

Coutances: Kalamansi or Coté Saint-Pierre

Saint-Denis-le-Vetu: La Baratte

Saint-Lô: l'Intuition* or Les Capucines

If in the summer, La Baie in Regnéville-sur-Mer

Blainveille-sur-Mer: Le Mascaret*

Barneville-Carteret: Marnage - la Marine

Cherbourg: La Pily* or Carabot

Grandcamp-Maisy: Restaurant la Marée

Caen: Ivan Vautier* or Magma

I stayed in Beynac a few years ago. Stayed at the Hotel du Chateau, which has a nice restaurant attached to it. The other place we ate was right at the parking lot for the Chateau - specialty was duck (confit, foie gras). Those are the ones I remember fondly.