The Musée des Années 30 is a must for lovers of the Art Déco period, with a small but interesting collection of art and sculpture from the 1930s. Look out for modernist sculptures by the Martel brothers, graphic designs, and Juan Gris still lifes and drawings. The highlights are the designs by avant-garde architects Perret, Le Corbusier and Fischer.
If your French is up to scratch sign up (with the museum) for an Art Déco themed tour around Boulogne. The morning part takes you around the town centre, which is peppered with 1930s gems; while the afternoon is dedicated to the museum's collections.