I'm not so sure at what age kids get the wow of cathedrals, scenic monasteries, even castles. Where I live we have a large medieval center city. My granddaughter is unfazed; she takes out a book and sits down to read. I recently had her in Paris. She was enthralled by Greek statues and Egyptian artifacts at the Louvre but impervious to the palace room decoration. When I took her to la Sainte Chapelle for a baroque concert, she loved the music but the décore again didn't catch her eye. We counted how many pieces of blue in a certain window, distinguished gothic from Romanesque arches, but architecture wasn't her thing. Although she had studied Rome and aquaducts in school, the Pont du Gard and Arena in Nîmes came in way below the nearby Haribo Bonbon museum. In Aiguës Mortes, we looked for masons' marks on cut stones-- which became a game, but the ramparts were just another wall.
Go to Annecy or Normandy. Great recommendation.
Edit: BTW, the heat wave here in France is predicted to break later in the week. We'll see. We're leaving for Collioure and the Pyrenees where 75 degree weather is forecast.
