What is the main conflict in Paris to the Moon by Adam Gopnik?

As a chronicle of an American family adjusting to life in a European society, Paris to the Moon belongs to a genre of writing that goes back centuries, to when America was a brash upstart on the "other side of the pond" from the socially and culturally mature Old Europe. Paris, in particular, has long held a fascination for American writers, as a city of beauty, romance, and cultural achievement rarely matched in the world.