The Cité de l'architecture & du patrimoine fills part of the Palais de Chaillot with French architecture at a scale that feels almost theatrical. Its great draw is the Hall of Casts, where full-size copies of church portals, towers, facades, and sculptural details let you study buildings from across France in one place.
Later galleries cover modern and contemporary architecture through models, drawings, and photographs. It is a strong choice near the Trocadéro if you want something more thoughtful than another Eiffel Tower viewpoint.