My sons bith got one on one trips with us to Paris, one son at 13 one at 14.
I also took our dzighter for first time when she was 11.
One son loved the Louvre ( and asked for a second visit, and no, he is not scholarly , lol, he was a skateboarded who pulled down C+ s except in woodwooding class lol).
The other son was not taken there . ( he has some issues so his trip was tailored to his needs) , but he liked going to a special exhibit of davinci drawings,,different strokes.
Both boys loved visiting th Catacombs, it was the elder boy who found out about them and put them on his list( all three of my children were required to compose a list with at least three sites on it, other than the ET lol)
All three kids liked the Invalids Army Museum.
Two of them loved Versailles , middle son was not taken there.
Daugnter loved the Orsay and liked the Cluny.
We all thought visit to the Shoah Memorial was touching..and no we are not jewish.
Oldest son and daughtter loved visiting Chantilly. Especially the Royal stables.
Took one son to Provins, world heritage site , entact anicent ramparts, saw the Birds of Prey show ( live outdoor shows) unfortunately think they limit winter hours.